Synthesis of porphyrins designed for attachment to electroactive surfaces via one or more carbon tethers

ABSTRACT

Porphyrin compounds having a surface attachment group coupled thereto at the 5 position are described. The surface attachment group has the formula: 
                         
wherein R is —CHCH 2  or —CCH and Ar is an aromatic group. Methods and intermediates useful for making such compounds are also described.

This invention was made with Government support under Grant No.MDA972-01-C-0072 from the DARPA Moletronics Program. The Government hascertain rights to this invention.

RELATED APPLICATIONS

This application is related to U.S. patent applications Ser. Nos.:

Ser. No. 10/628,868, filed Jul. 28, 2003, titled Attachment of OrganicMolecules to Group III, IV, or V Substrates;

Ser. No. 10/742,596, filed Dec. 19, 2003;

Ser. No. 10/641,412, filed Aug. 15, 2003, titled Scalable Synthesis ofDipyrromethanes;

Ser. No. 10/164,181, filed Sep. 3, 2003, titled Facile Synthesis of1,9-diacyldiprromethanes;

Ser. No. 10/698,255, filed Oct. 31, 2003, titled Synthesis ofPhosphono-substituted Porphyrin Compounds for Attachment to Metal OxideSurfaces; and

Ser. No. 10/867,512, filed Jun. 14, 2004, titled A New Route toFormyl-Porphyrins;

the disclosures of which are incorporated by reference herein in theirentirety.

FIELD OF THE INVENTION

This invention concerns methods and intermediates for the synthesis ofporphyrins, particularly porphyrins suited to attachment toelectroactive surfaces.

BACKGROUND OF THE INVENTION

The field of molecular electronics has been driven in part by theprospect that devices that rely on the bulk properties of semiconductorswill fail to retain the required characteristics to function whenfeature sizes reach nanoscale dimensions. As a consequence, there hasbeen much interest in developing molecular-based electronic materialsfor use in both memory architectures and circuit elements.¹ Towards thisgoal, we have been engaged in a program aimed at constructing devicesthat use the properties of molecules to store information.²⁻⁶ In theseapproaches, a collection of redox-active porphyrinic molecules attachedto an electroactive surface serves as the active storage medium, andinformation is stored in the discrete redox states of the molecules. Thefocus of this work has been developing a hybrid architecture, where themolecular material is attached to a semiconductor platform. Theimplementation of hybrid molecular/semiconductor architectures as atransition technology leverages the vast infrastructure of thesemiconductor industry with the advantages afforded by molecular-basedactive media.

The success of such a hybrid architecture requires, in general, (1) astraightforward means of attaching porphyrins to an electroactivesurface, particularly large-wafer silicon, and (2) a robust linkage thatcan withstand large numbers of redox cycles. A number of methods havebeen developed for covalent attachment of organic molecules to siliconsurfaces.⁷ For example, the reaction of Si (hydrogen-passivated orchlorine-modified) with an alcohol affords the self-assembled filmcontaining RO—Si linkages. However, the reaction requires use of neatliquids or a very high concentration of the molecules to beattached.⁸⁻¹¹ Porphyrins generally have low solubility in organicsolutions, with concentrations of ˜50 mM being a typical upper limit.The method we previously developed for attaching porphyrins to Siplatforms (either hydrogen-passivated or iodine-modified) involveddepositing a drop of solution containing the porphyrin compound in ahigh-boiling solvent (e.g., benzonitrile, bp 191° C.) onto aphotolithographically patterned micron-size Si electrode, followed byheating at ˜170° C. for several hours, during which time additionalsolvent was added to the sample area.⁶ This method afforded attachmentof porphyrins⁶ (and ferrocenes^(3,6)) to Si(100) via tethers that areterminated with OH, SAc, and SeAc groups, yielding RO—Si, RS—Si, andRSe—Si linkages (the acetyl protecting group is cleaved upon attachment)where R represents the tether and accompanying redox-active unit.¹² Thisprocedure produced high quality monolayers useful for academic studiesbut was unsuited for reproducible fabrication of memory chips on largeSi wafers. In addition, in the past few years it has become apparentthat more stable monolayers are generally obtained with carbosilanelinkages (RC—Si) than alkoxysilane linkages (RO—Si). Achieving a stablelinkage of the redox-active unit to the Si surface is essential becauseas many as 10¹⁵ cycles may be encountered over an operational lifetimein a memory chip.¹³

A number of methods have been developed for derivatizing siliconsurfaces via carbosilane linkages.⁷ The methods include pyrolysis ofdiacyl peroxides,^(14,15) reaction of Grignard reagents (withhalogenated silicon surfaces),¹⁶ and electrografting of aryldiazoniumsalts,¹⁷ alkyl halides,¹⁸ or Grignard reagents.¹⁹ Alkenes have beenemployed for attachment to Si via thermal,^(15,20,21) free radical,¹⁵photochemical (UV),²²⁻²⁴ and Lewis-acid mediated reactions.^(25,26)Alkynes have been less studied but generally appear to react via thesame methods as for alkenes, including thermal,²⁷ free radical,¹⁵photochemical,²⁸ Lewis-acid mediated,^(26,28) and electrograftingprocesses.²⁸

SUMMARY OF THE INVENTION

The thermal attachment methods (typically ˜100° C.) with alkenes oralkynes are attractive for attaching porphyrinic compounds tolarge-scale Si wafers. However, the requirement for use of very highconcentrations of reactants appeared to exclude such an application. Thepresent invention provides for, among other things, the convenientsynthesis of such compounds in useful forms.

A first aspect of the present invention is a porphyrin compound having asurface attachment group coupled thereto at the 5 position, said surfaceattachment group having the formula:

wherein:

R is —CHCH₂ or —CCH;

Ar is an aromatic group;

m is 0 to 4;

n is 0 to 6; and

p is 0 or 1 to 3;

said porphyrin compound preferably subject to the proviso that n is atleast 1 or m is at least 2, and p is at least 1.

A second aspect of the present invention is a method of making aporphyrin compound having a surface attachment group coupled thereto atthe 5 position, said surface attachment group having the formula:

wherein R, Ar, m, n and p are as described above, the method comprising:(a) reacting a dipyrromethane with a dipyrromethane-1,9-dicarbinol toproduce a reaction product; and then (b) oxidizing said reaction productto produce said porphyrin compound, wherein either or both of saiddipyrromethane and said dipyrromethane-1,9-dicarbinol is substitutedwith said surface attachment group at the 5 position.

A further aspect of the invention is a method of making a porphyrincompound having a vinyl surface attachment group coupled thereto at the5 position, said method comprising: (a) halogenating a porphyrin at the5 position to produce an intermediate; and then (b) reacting saidintermediate with a vinyl stannane in the presence of a palladium (0)catalyst in a Stille cross-coupling reaction to produce said porphyrincompound having a vinyl surface attachment group coupled thereto at the5 position.

A further aspect of the invention is a dipyrromethane compound having asurface attachment group coupled thereto at the 5 position, said surfaceattachment group having the formula:

wherein R, Ar, m, n and p are as described above, said dipyrromethanecompound preferably subject to the proviso that n is at least 1 or m isat least 2, and p is at least 1. In some embodiments the dipyrromethaneis a 1,9-diacyldipyrromethane.

A further aspect of the present invention is a method of making adipyrromethane compound having a surface attachment group coupledthereto at the 5 position, said surface attachment group having theformula:

wherein R, Ar, m, n and p are as described above; said methodcomprising: reacting a precursor compound of the formula:

where X is an aldehyde or acetal group, with a pyrrole to produce saiddipyrromethane compound having said surface attachment group substitutedtherein at the 5 position.

A further aspect of the present invention is a method of making a1,9-diacyldipyrromethane metal complex, comprising: (a) acylating adipyrromethane compound having a surface attachment group coupledthereto at the 5 position, said surface attachment group having theformula:

wherein R, Ar, m, n and p are as described above, to form a mixedreaction product comprising a 1,9-diacyldipyrromethane; (b) combiningsaid mixed reaction product with a compound of the formula R′₂MX₂ in thepresence of a base, where R′ is alkyl or aryl, M is Sn, Si, Ge, or Pb,and X is halo, OAc, acac or OTf, to form a metal complex of the formulaDMR′₂ in said mixed reaction product, wherein DH₂ is a1,9-diacyldipyrromethane; and then (c) separating said metal complexfrom said mxied reaction product.

The present invention is explained in greater detail in the drawingsherein and the specification set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Fast-scan cyclic voltammograms (100 Vs⁻¹) of monolayers of Zn1and Zn7 on p-type Si(100) microelectrodes. The solvent/electrolyteoverlayer is composed of propylene carbonate containing 1.0 M Bu₄NPF₆.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is explained in greater detail below. Thisdescription is not intended to be a detailed catalog of all thedifferent ways in which the invention may be implemented, or all thefeatures that may be added to the instant invention. For example,features illustrated with respect to one embodiment may be incorporatedinto other embodiments, and features illustrated with respect to aparticular embodiment may be deleted from that embodiment. In addition,numerous variations and additions to the various embodiments suggestedherein will be apparent to those skilled in the art in light of theinstant disclosure which do not depart from the instant invention.Hence, the following specification is intended to illustrate someparticular embodiments of the invention, and not to exhaustively specifyall permutations, combinations and variations thereof.

The term “alkyl,” as used herein, refers to a straight or branched chainhydrocarbon containing from 1 to 10 carbon atoms. Representativeexamples of alkyl include, but are not limited to, methyl, ethyl,n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl,n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl,2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl,n-decyl, and the like, which may be substituted or unsubstituted.

The term “aryl,” as used herein, refers to a monocyclic carbocyclic ringsystem or a bicyclic carbocyclic fused ring system having one or morearomatic rings. Representative examples of aryl include, azulenyl,indanyl, indenyl, naphthyl, phenyl, tetrahydronaphthyl, and the like,which may in turn be substituted or unsubstituted.

“Halo” as used herein includes fluoro, chloro, bromo, and iodo.

“Dipyrromethane” as used herein includes both unsubstituted andsubstituted dipyrromethanes, which may be substituted one or more timesat the 1, 2, 3, 5, 7, 8 or 9 positions with any suitable substituentsuch as halo, carbonyl, alkyl, fluoroalkyl including perfluoroalkyl,aryl (e.g., aryl at the 5 position; alkyl at the 1 and/or 9 position),fluoroaryl including perfluoroaryl, etc. Dipyrromethanes may be coupledto porphyrinic macrocycles at any suitable position on thedipyrromethanes, including the 1, 2, 3, 5, 7, 8, or 9 position.

“Aldehyde group” as used herein refers to a group of the formula —C(═O)Hor —RC(═O)H, in which a carbonyl group is bonded to one hydrogen atomand to an R group. Any suitable organic R group, or hydrogen as an Rgroup, may be used in the aldehyde, including aliphatic (e.g., alkyl)and aromatic or aryl R groups (all of which may be substituted orunsubstituted), with particular examples including porphyrin, dipyrrin,and diacyldipyrromethane R groups (all of which may be substituted orunsubstituted). Examples of particular aldehydes that may be usedinclude but are not limited to: formaldehyde, paraformaldehyde,acetaldehyde, propionaldehyde, n-butyraldehyde, benzaldehyde,p-nitrobenzaldehyde, p-tolualdehyde, salicylaldehyde,phenylacetaldehyde, α-methylvaleraldehyde, β-methylvaleraldehyde,γ-methylvaleraldehyde, 4-pyridine carboxaldehyde,pentafluorobenzaldehyde, 4-ethynylbenzaldehyde,4-[2-(triisopropylsilyl)ethynyl]benzaldehyde,4-[3-methyl-3-hydroxy-but-1-ynyl)benzaldehyde,4-(S-acetylthiomethyl)benzaldehyde,4-(Se-acetyl-selenomethyl)benzaldehyde, 4-(hydroxymethyl)benzaldehyde,4-vinylbenzaldehyde, 4-allylbenzaldehyde, 4-cyanobenzaldehyde,4-iodobenzaldehyde, 4-(bromomethyl) benzaldehyde,4-(2-bromoethyl)benzaldehyde, 4-(1,3-dithiolan-2-yl)benzaldehyde,4-(1,3-dithian-2-yl)benzaldehyde,4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzaldehyde,4-(acetoxymethyl)benzaldehyde,4-[2-(trimethylsilyl)ethoxy-carbonyl]benzaldehyde,4-methoxycarbonylbenzaldehyde,5-[4-(di-tert-butyloxy-phosphoryl)benzaldehyde,5-[4-(diethoxyphosphoryl)benzaldehyde,5-[4-(di-tert-butyloxyphosphorylmethyl)benzaldehyde,5-[4-(diethoxyphosphorylmethyl) benzaldehyde,1,1,1-tris[4-(diethoxyphosphorylmethyl)phenyl]-1-(4-formylphenyl)methane,1,1,1-tris[4-(S-acetylthiomethyl)phenyl]-1-(4-formylphenyl)methane,3-(S-acetylthiomethyl)benzaldehyde, 3,5-diethynylbenzaldehyde,3,5-bis[2-(triisopropyl-silyl)ethynyl]benzaldehyde,4-(5,10,15-tri-p-tolylporphinatozinc(II)-20-yl)benzaldehyde,4-(5,10,15-tri-p-tolylporphin-20-yl)benzaldehyde,4-(dipyrrin-5-yl)benzaldehyde,4-[1,9-bis(4-methylbenzoyl)dipyrromethan-5-yl]benzaldehyde,4-ferrocenylbenzaldehyde, propargyl aldehyde, bromomethylpropargylaldehyde, chloromethylpropargyl aldehyde, S-acetylthiomethylpropargylaldehyde, 4-(hydroxymethyl)phenylpropargyl aldehyde,hydroxyacetaldehyde, and pyruvic aldehyde.

“Acetal group” as used herein refers to compounds known as “latentaldehydes” that produce the same products as can be produced with analdehyde as described above in reactions of the present invention.Acetal groups are in general compounds of the general formula—RC(—OR′)(—OR″)H or —C(—OR′)(—OR″)H, wherein R is as given in connectionwith aldehydes above and R′ and R″ are any suitable organic substituentsuch as alkyl or aryl (e.g., methyl, ethyl, propyl, butyl, phenyl).

“Porphyrin” as used herein refers to a cyclic structure typicallycomposed of four pyrrole rings together with four nitrogen atoms and tworeplaceable hydrogens for which various metal atoms can readily besubstituted. Porphyrins may be substituted or unsubstituted. A typicalporphyrin is hemin.

“Bronsted acid” as used herein refers to a molecular entity (andcorresponding chemical species) that is a proton donor to a base. Anysuitable Bronsted acid may be used as a catalyst, with examplesincluding but not limited to: trifluoroacetic acid, trichloroaceticacid, oxalic acid, taurine, malonic acid, formic acid, acetic acid, andNH₄Cl.

“Lewis acid” as used herein refers to a molecular entity (andcorresponding chemical species) that is an electron-pair acceptor andtherefore able to react with a Lewis base to form a Lewis adduct, bysharing the electron pair furnished by the Lewis base.

Applicants specifically intend the disclosures of all US patentreferences cited herein to be incorporated by reference herein in theirentirety.

Porphyrin compounds and synthesis thereof. As noted above, the presentinvention provides porphyrin compounds having a surface attachment groupcoupled thereto at the 5 position, the surface attachment group havingthe formula:

wherein:

R is —CHCH₂ or —CCH (in some embodiments preferably —CHCH₂);

Ar is an aromatic group(in some embodiments preferably a phenyl group);

m is 0, 1, 2, 3 or 4 (in some embodiments preferably at least 2; inother embodiments preferably 0, 1 or 2);

n is 0, 1 or 2 to 3, 4, 5 or 6 (in some embodiments preferably at least1, e.g., 1 or 2) (in some embodiments m and n together total 1, 2, 3, 4or 5); and

p is 0, 1, 2 or 3 (in some embodiments preferably 1 or 2);

Such compounds can be produced by the methods and procedures set forthin greater detail below.

A method of making a porphyrin compound having a surface attachmentgroup coupled thereto at the 5 position as described above (which methodis exemplified by Scheme 5 below) comprises: (a) reacting (i.e.,condensing) a dipyrromethane with a dipyrromethane-1,9-dicarbinol toproduce a reaction product; and then (b) oxidizing said reaction productto produce said porphyrin compound, wherein either or both of saiddipyrromethane and said dipyrromethane-1,9-dicarbinol is substitutedwith said surface attachment group at the 5 position. In general, thecondensing step is carried out in a polar or nonpolar solvent in thepresence of a Lewis acid followed by oxidation with an oxidizing agentsuch as DDQ in accordance with known techniques. In some embodiments thesolvents used to carry out the present invention preferably have adielectric constant of about 20, 15, or 10 or less, at room temperature(i.e., 25° C.). The solvent may be a single compound or mixturesthereof. Preferably the solvent is non-aqueous. Particular examples ofsuitable solvents include, but are not limited to, chlorinated aliphatichydrocarbons (e.g., dichloromethane, chloroform, 1,2-dichloroethane,1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,1-dichloroethylene,cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene,etc.); chlorinated aromatic hydrocarbons (e.g., chlorobenzene,1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene,1-chloronaphthalene, etc.); hydrocarbons (e.g., benzene, toluene,xylene, ethylbenzene, mesitylene, durene, naphthalene); ethers (e.g.,ethyl ether, propyl ether, tetrahydrofuran, p-dioxane, anisole, phenylether, etc.); esters (e.g., ethyl acetate, methyl acetate, ethylbenzoate, butyl phthalate, etc.); glymes (e.g., 2-methoxyethanol,2-butoxyethanol), and other solvents such as carbon disulfide, tributylborate, etc., and mixtures of the foregoing. Note that some solvents maybe less preferred: for example, an oxygen in diethyl ether maycoordinate with and tie up the Lewis acid, and hence be less preferred.Any suitable electron-pair acceptor may be used as the Lewis acidcatalyst in the present invention, including, but not limited to, CsCl,SmCl₃.6H₂O, InCl₃, CrF₃, AlF₃, Sc(OTf)₃, TiF₄, BEt₃, GeI₄, EuCl₃.nH₂O,LaCl₃, Ln(OTf)₃ where Ln=a lanthanide, etc. The concentration may range,for example, from 0.001 or 0.01 mmol/L to 100 or 500 mmol/L, or more.Specific examples of Lewis acids and suitable concentrations thereofinclude InCl₃ (0.32 mmol/L), Sc(OTf)₃ (0.32 mmol/L), Yb(OTf)₃ (1.0mmol/L), and Dy(OTf)₃ (0.32 mmol/L). See, e.g., Lindsey et al., USPatent Application 2003/0096978 (May 22, 2003). The reaction conditionsof the present invention are not critical. In general, the reactions maybe carried out at any suitable temperature and pressure, such as roomtemperature and ambient pressure. In general the reactions are rapid(e.g., are carried out for a time of from 1 to 10 minutes), andpreferably are carried out within a time of 1 to 2 hours. Thedipyrromethane-1,9-dicarbinol can be produced by reducing a1,9-diacyldipyrromethane to form the dipyrromethane 1-9-dicarbinol, inaccordance with known techniques.

Vinyl porphyrin compoundss and synthesis thereof. A further aspect ofthe invention is a method (an example of which is illustrated in Scheme6 below) of making a porphyrin compound having a vinyl surfaceattachment group coupled thereto at the 5 position, said methodcomprising: (a) halogenating a porphyrin at the 5 position to produce anintermediate; and then (b) reacting said intermediate with a vinylstannane in the presence of a palladium (0) catalyst in a Stillecross-coupling reaction to produce said porphyrin compound having avinyl surface attachment group coupled thereto at the 5 position. TheStille reaction is known and can be carried out in accordance with knowntechniques, such as those described in U.S. Pat. Nos. 6,482,851;6,380,394, 6,197,922; 6,136,157; and 5,849,922, or variations thereofthat will be apparent to those skilled in the art in light of thedisclosure provided herein. In general, the Stille reaction may becarried out with a palladium(0) catalyst, typically with a trialkyl ortriaryl P or As compound as the ligand(s), and with a vinyl stannane,typically a (vinyl)trialkylstannane, as the other reactant. The reactionconditions are not critical, and the reaction may be convenientlycarried out in a non-polar organic solvent such as tetrahydrofuran,toluene, or mixture thereof, at any suitable temperature (e.g., 0 to150° C.). The porphyrin itself may be conveniently produced by reactinga dipyrromethane with a dipyrromethane-1,9-dicarbinol to produce areaction product; and then oxidizing the reaction product to producesaid porphyrin.

Dipyrromethanes and synthesis thereof. As also noted above, a furtheraspect of the present invention is a dipyrromethane compound having asurface attachment group coupled thereto at the 5 position, said surfaceattachment group having the formula:

wherein R, Ar, m, n and p are as described above. Such compounds include1,9-diacyldipyrromethane (as exemplified by Scheme 4 below). Suchcompounds can be made by reacting a precursor aldehyde or acetalcompound of the formula:

where X is an aldehyde or acetal group and R, Ar, m, n and p are asgiven above with a pyrrole to produce the desired dipyrromethanecompound having the surface attachment group substituted therein at the5 position. Such methods are exemplified by Scheme 3 below. In general,such methods comprise the step of (a) providing a reaction systemcomprising, consisting of or consisting essentially of an aldehyde oracetal as described above, excess pyrrole and a catalyst. The amount ofthe aldehyde or acetal in the reaction system will vary depending uponthe particular aldehyde or acetal used, but in general the molar ratioof the pyrrole to the aldehyde or acetal is 50:1 to 5,000:1. Stateddifferently, in general the amount of aldehyde or acetal is from 0.05 or0.5 to 1 or 5 percent by weight of the system, or more, and the amountof pyrrole in the system is generally from 95 or 98 to 99 or 99.9percent by weight of the system, or more. The catalyst may be a Bronstedacid or a Lewis acid, and the amount of catalyst in the system is, ingeneral, from 0.01 or 0.1 to 0.5 or 1 percent by weight of the system,or more. Stated otherwise, the molar amount of acid is generally about0.01 to 100 times the molar amount of aldehyde or acetal in the system.Preferably the system contains not more than 5 or 10 percent by weightwater as noted above, and more preferably the system is non-aqueous. Thenext step of the method involves (b) reacting the aldehyde or acetalwith the pyrrole in the reaction system to form the dipyrromethanetherein. The reaction temperature is not critical, but in general may befrom −20 or 0 to 100° C., or more, and is preferably room temperature.The pressure of the system during the reaction is not critical, but isconveniently ambient pressure. The reaction may be carried out for anysuitable time, typically up to 24 hours, and preferably up to one hour.After the reaction step, the method preferably involves (c) quenchingthe reaction system by adding a base thereto. The base is preferablyadded without simultaneously adding an organic solvent or water to thereaction system, and in a preferred embodiment the reaction system henceremains non-aqueous during quenching. In general, at least 1 equivalentof base per acid catalyst, up to 10 equivalents of base per acidcatalyst, is added. The base may conveniently be added as a pure or neatsubstance (which may be a liquid or dry powder), a slurry in pyrrole,etc. The method then may then involve (d) separating the catalyst fromthe (preferably non-aqueous) reaction system, preferably by a filtrationtechnique (such as suction filtration or pressure filtration) or agravity technique (such as centrifugation or settling, e.g., withsubsequent decanting); and then (e) separating the pyrrole from the(preferably non-aqueous) reaction system to produce the dipyrromethaneas a residual (e.g., by pumping off or evaporating the pyrrole). Asnoted above, the method may optionally include the further step of (f)crystallizing the resultant dipyrromethane, which crystallization may becarried out in accordance with conventional techniques.

Making 1,9-diacyldipyrromethane metal complexes. A further aspect of thepresent invention is method of making a 1,9-diacyldipyrromethane metalcomplex (exemplified by Scheme 4 below). In general such methodscomprise: (a) acylating a dipyrromethane compound having a surfaceattachment group coupled thereto at the 5 position, said surfaceattachment group having the formula:

wherein R, Ar, m, n and p are as described above, to form a mixedreaction product comprising a 1,9-diacyldipyrromethane; (b) combiningsaid mixed reaction product with a compound of the formula R₂MX₂ in thepresence of a base, where R is alkyl or aryl, M is Sn, Si, Ge, or Pb,and X is halo, OAc (where OAc is acetate), acac (acetylacetonate) or OTf(where OTf is triflate), to form a metal complex of the formula DMR₂ insaid mixed reaction product, wherein DH₂ is a 1,9-diacyldipyrromethane;and then (c) separating said metal complex from said mxied reactionproduct. Suitable bases include but are not limited to triethylamine,tributylamine, N,N-diisopropylamine, DBU, DBN, and2,6-di-tert-butylpyridine. The time and temperature of the combiningstep is not critical, but may for example be from 1 or 2 minutes to 24hours in duration, and is most conveniently carried out for 10 minutesto two hours, at a temperature range of −20° C. to 50 or 100° C. or more(e.g., room temperature). Any suitable organic solvent may be used,including but not limited to methylene chloride, chloroform,1,2-dichloroethane, toluene, chlorobenzene, etc. Where complexation ofthe diacyldipyrromethane is carried out with a compound of the formulaR₂MX₂, that compound may be free in the reaction solution or immobilizedon a solid support such as a polymer support, where the groups Rconstitute a portion of the polymer or are otherwise coupled to thepolymer (with immobilization on the solid support facilitating thesubsequent separation of the acylated dipyrromethane product). Themethods described herein may further comprise the step of: (d) treatingthe metal complex with an acid to produce a 1,9-diacyldipyrromethane.Any suitable acid may be used, including but not limited totrifluoroacetic acid, trichloroacetic acid, acetic acid, HCl,p-toluenesulfonic acid. In other embodiments, the methods describedherein may further comprise the steps of: (d) reducing the metal complexwith a base such as NaBH₄ to form a diol from the1,9-diacyldipyrromethane; and then (e) condensing the diol with adipyrromethane to form a porphyrin ring compound therefrom.

Utility. The porphyrin compounds of the invention are useful, amongother things, for the production of polymers thereof which may beimmobilized or coupled to a substrate and used as light harvesting rods,light harvesting arrays, and solar cells, as described for example inU.S. Pat. No. 6,407,330 to Lindsey et al. or U.S. Pat. No. 6,420,648 toLindsey. Porphyrinic macrocycles or porphyrin compounds of the inventionare also useful immobilized to a substrate for making charge storagemolecules and information storage devices containing the same. Suchcharge storage molecules and information storage devices are known anddescribed in, for example, U.S. Pat. No. 6,208,553 to Gryko et al.; U.S.Pat. No. 6,381,169 to Bocian et al.; and U.S. Pat. No. 6,324,091 toGryko et al. The porphyrinic macrocycle may comprise a member of asandwich coordination compound in the information storage molecule, suchas described in U.S. Pat. No. 6,212,093 to Li et al. or U.S. Pat. No.6,451,942 to Li et al.

The present invention is explained in greater detail in the non-limitingExamples set forth below.

EXPERIMENTAL

The success of thermal attachment method with alcohol tethers (both forporphyrins and other types of molecules)⁶ combined with the fact thatporphyrins are known to be stable at very high temperatures (400° C.under inert atmosphere conditions)⁴ where other types of organicmolecules decompose prompted us to explore very high temperatureprocessing strategies. Two high-temperature processing conditions thatenable attachment to Si(100) of porphyrins containing a wide variety offunctional groups were developed. The conditions entail directdeposition of the sample onto the Si substrate or sublimation onto theSi substrate. The porphyrins examined initially were those that bearfunctional groups known to attach to silicon, such as the benzyl alcoholporphyrin Zn1.⁶ It was subsequently found that a number of hydrocarbontethers also afford attachment. The latter finding prompted thesynthesis of a systematic set of porphyrins bearing a wide variety ofhydrocarbon tethers.

In this application, we first describe the synthesis of the porphyrinsbearing hydrocarbon tethers. We then describe the two high-temperatureprocessing methods for attachment to silicon substrates. Taken together,this work greatly expands the scope of porphyrins that can be attachedto silicon and enables attachment under conditions suitable forreproducible fabrication.

Results and Discussion

1. Molecular Design. The porphyrins examined herein are designed toprobe (1) the effects of the tether (length, composition, terminalfunctional group) on the ease of attachment and quality of the resultingmonolayers on silicon, (2) the ability to attach to silicon via twolinkages, and (3) the effects of the size and pattern of nonlinkingsubstituents on the charge-storage properties of the resultingmonolayers on silicon. The motivation for these studies stems from thefact that the electron-transfer rates vary depending on the nature ofthe tether^(2,5) and on the surface density⁶ of the attachedredox-active molecules. Most of the porphyrins are zinc chelates, bear atether at one meso site, and incorporate inert groups at the threenonlinking meso sites. Within this class, one set of molecules variesthe nature of the surface attachment group (iodo, bromomethyl, ethyne,vinyl, allyl; Zn2-Zn7; Chart 1) with mesityl groups at the threenonlinking meso sites. A second set of molecules varies the steric bulkof the nonlinking meso substituents (p-tolyl vs. mesityl) and the lengthof the tether (4-vinylphenyl vs. 4-allylphenyl) [Zn6 and Zn7, Chart 1;Zn10 and Zn11, Chart 2]. A third set incorporates alkene-terminatedtethers of different length (vinyl, allyl, 3-butenyl, 4-vinylphenyl,4-allylphenyl) with nonlinking p-tolyl groups [Zn10-Zn14, Chart 2]. Afourth set of molecules employs a fixed tether (4-allylphenyl) andvaries the size of the two flanking meso substituents (p-tolyl, methyl)and the distal meso substituent (p-tolyl, mesityl, 2,4,6-triethylphenyl)[Zn14-Zn19, Chart 3]. Two additional zinc porphyrins bear two halo ortwo vinyl groups at porphyrin β positions. The final porphyrin is a freebase, core-modified monothia-porphyrin with two bromo groups at theβ-thiophene positions. Porphyrins Zn2,²⁹ Zn3,³⁰ Zn4,³¹ and Zn5³² havebeen prepared previously.

2. Synthesis of Porphyrins Bearing Meso-linked Tethers. A. StatisticalApproach. Two A₃B-porphyrins were prepared [A=mesityl; B=4-vinylphenyl(Zn6) or 4-allylphenyl (Zn7)] for attachment to Si(100). Porphyrinsbearing three meso-mesityl groups are not available via rationalsynthesis but can be prepared via statistical mixed-aldehydecondensations. The synthesis of Zn6 is shown in Scheme 1.4-Iodobenzaldehyde was protected as the dimethyl acetal (20) in 96%yield. Kumada cross-coupling³³ of 20 and vinylmagnesium bromide affordedacetal 21 in 64% yield. Removal of the acetal protecting group of 21 wasnot attempted given the high reactivity of the styryl moiety undereither acidic or basic conditions. A mixed-aldehyde condensation³⁴ wascarried out at elevated concentration³⁵ using BF₃.O(Et)₂-EtOHcocatalysis³⁶ with acetal 21, mesitaldehyde and pyrrole. Oxidation withDDQ afforded a mixture of porphyrins. The porphyrin mixture was treatedwith zinc acetate to give the corresponding zinc porphyrins. Porphyrinsthat have substituents of similar polarity but different degrees offacial encumbrance are more readily separated as the zinc chelates thanas the free base forms.³¹ Chromatography afforded Zn6 in 14% yield.

Allyl-porphyrin Zn7 was prepared as shown in Scheme 2. Acetal 22³⁷ wastreated with a biphasic solution³⁸ of aqueous TFA and CH₂Cl₂ to afford4-allylbenzaldehyde (23) in 81% yield. A mixed-aldehyde condensation³⁴of 23 with mesitaldehyde and pyrrole was carried out usingBF₃.O(Et)₂-EtOH cocatalysis³⁶ followed by DDQ oxidation. Zinc insertionand chromatographic workup afforded Zn7 in 12% yield.

B. Rational Approach. To achieve a scalable synthesis, we haveinvestigated meso substituents that are compatible with a rationalsynthesis of porphyrins. The rational synthesis relies on thecondensation of a dipyrromethane and a dipyrromethane-dicarbinol.³⁹ Thesynthesis of the dipyrromethanes and 1,9-diacyldipyrromethanes isdescribed below.

Synthesis of Dipyrromethanes. The synthesis of dipyrromethanes can beachieved via the one-flask reaction of an aldehyde with excesspyrrole.⁴⁰⁻⁴² The synthetic method has generally employed TFA as theacid catalyst and workup via chromatography and Kugelrohrdistillation,⁴¹ but recently we found that milder acids could beemployed in conjunction with a more simple purification procedure viadirect crystallization.⁴² These procedures were employed to preparedipyrromethanes 24-31 (Scheme 3). In method A,⁴² an aldehyde (21, 23,mesitaldehyde, or 4-pentenal) was condensed with pyrrole (100 eq) underInCl₃ (0.1 eq) catalysis at room temperature for 1.5 h, followed byquenching the reaction with powdered NaOH, filtration to removeneutralized catalyst, removal of pyrrole, and recrystallization (orcolumn chromatography). In this manner, the new dipyrromethanes 25, 27,28 and the known dipyrromethane 30⁴² were prepared in good yields.Application of method A to 3-butenal diethyl acetal was unsuccessful.Therefore, the latter was condensed with excess pyrrole (40 eq) underTFA (0.1 eq) catalysis at room temperature for 10 min (Method B).⁴¹Analysis of the crude reaction mixture by GC showed a much higherpercentage of N-confused dipyrromethane (˜25%) than is typicallyobserved (˜5%) under these conditions. Nevertheless, the tworegioisomers were readily separated by column chromatography affording24 as a viscous oil in 36% yield. The known dipyrromethanes 26⁴³ and29⁴¹ were also prepared following Method B. The condensation of2,4,6-triethylbenzaldehyde⁴⁴ with excess pyrrole (100 eq) under MgBr₂(0.5 eq) catalysis at room temperature for 1 h (Method C)⁴² afforded 31as a viscous oil in 57% yield after column chromatography. All attemptsto prepare 5-vinyldipyrromethane (to serve as a precursor to porphyrinZn10) from acrolein or acrolein diethyl acetal via method A or B wereunsuccessful.

Scheme 3

R X Method Product Yield

—CH(OEt)₂ B 24 36%

—CHO A 25 78% TMS—≡— —CHO B 26 70%(ref. 43)

—CH(OMe)₂ A 27 65%

—CHO A 28 61%

—CHO B 29 33%(ref. 41)

—CHO A 30 53%(ref. 42)

—CHO C 31 57% A = InCl₃ (0.1 eq), pyrrole (100 eq) rt, 1.5 h B = TFA(0.1 eq), pyrrole (40 eq), rt, 10 min C = MgBr₂ (0.5 eq), pyrrole (100eq), rt, 1 h

Synthesis of 1,9-Diacyldipyrromethanes. The synthesis of several1,9-diacyldipyrromethanes is shown in Scheme 4. Treatment of adipyrromethane with EtMgBr in toluene followed by reaction with an acidchloride typically affords a mixture of the 1-acyldipyrromethane and1,9-diacyldipyrromethane.³⁹ Acyldipyrromethanes typically affordamorphous powders upon attempted crystallization and streak extensivelyon column chromatography. To facilitate isolation of the1,9-diacyldipyrromethane, the crude acylation mixture is treated withdibutyltin dichloride. The diacyldipyrromethane-tin complex, which formsselectively, typically is non-polar and crystallizes readily.⁴⁵

Scheme 4

R¹ R² X Product Yield

—Cl 32-SnBu₂ 57%

—Cl 33-SnBu₂ 52%

—Cl 34-SnBu₂ 39%

—CH₃ —Br 35-SnBu₂ 57%

In this manner, each dipyrromethane (28-31) was separately treated withEtMgBr in toluene followed by reaction with the appropriate acidchloride (p-toluoyl chloride or acetyl bromide). Subsequent reactionwith dibutyltin dichloride gave the corresponding tin complex, which wasreadily isolated by passage through a silica pad followed byprecipitation from MeOH. The diacyldipyrromethane-tin complexes32-SnBu₂-35-SnBu₂ were isolated in yields of 39-57%.

Synthesis of Porphyrins. The meso-substituted porphyrins Zn9 andZn11-Zn19 were prepared by reaction of a dipyrromethane and adipyrromethane-dicarbinol (Scheme 5). The dipyrromethane-dicarbinolswere prepared by reduction with NaBH₄ of the corresponding1,9-diacyldipyrromethane-tin complex⁴⁵ or of the unsubstituted1,9-diacyldipyrromethane.³⁹ The complete reduction of the tin(IV)complexes requires a slightly longer reaction time (˜2 h) versus that ofthe uncomplexed diacyldipyrromethane (40 min). Thedipyrromethane+dipyrromethane-dicarbinol condensation was performed atroom temperature with catalysis by TFA (30 mM) in CH₃CN³⁹ or Yb(OTf)₃(3.2 mM) in CH₂Cl₂.⁴⁶ Subsequent oxidation with DDQ and zinc metalationafforded the target porphyrin.

Scheme 5

Entry Components R¹ R² R³ Conditions Product Yield 1 32 + 26

—≡—TMS A Zn9 13% 2 32-SnBu₂ + 24

B Zn11 44% 3 32-SnBu₂ + 25

B Zn12 42% 4 32 + 27

A Zn13 26% 5 32-SnBu₂ + 28

B Zn14 23% 6 33-SnBu₂ + 28

B Zn15 21% 7 34-SnBu₂ + 28

B Zn16 10% Enry Components R³ R² R¹ Conditions Product Yield 835-SnBu₂ + 29

—CH₃

B Zn17 15% 9 35-SnBu₂ + 30

—CH₃

B Zn18 19% 10 35-SnBu₂ + 31

—CH₃

B Zn19 9% A = TFA, MeCN, rt B = Yb(OTf)₃, CH₂Cl₂, rt

The use of mild Lewis acids in CH₂Cl₂ generally affords slightly higheryields and a more facile workup than use of TFA in CH₃CN. However,attempts to prepare Zn9 (Entry 1) using either InCl₃ or Yb(OTf)₃ gavelower yields (3-11%) than with TFA (13%). The yields of porphyrins Zn16and Zn19 were somewhat low (˜10%), which is attributed to the bulky2,4,6-triethylphenyl moiety. Also, porphyrins bearing meso-methyl groups(Entries 8-10) gave lower yields than the analogous porphyrins bearingmeso-p-tolyl groups (Entries 5-7). In each case, the porphyrin-formingreaction was rapid (<30 min). Analysis by laser desorption massspectrometry (LDMS)⁴⁷ of the crude reaction mixtures after bulkoxidation showed no evidence of the presence of any other porphyrinspecies.

One porphyrin that was not available via this route was thevinyl-porphyrin Zn10, owing to the lack of access to5-vinyldipyrromethane (vide supra). The synthesis of Zn10 was achievedfollowing the route outlined in Scheme 6. Diacyldipyrromethane 32⁴⁸ wasreduced with NaBH₄ and the resulting 32-diol was condensed withdipyrromethane (36)^(41,49) in CH₂Cl₂ containing Yb(OTf)₃ at roomtemperature. Subsequent oxidation with DDQ afforded free base porphyrin37 in 33% yield. Porphyrin 37 was iodinated at the meso-position usingI₂ and (CF₃CO₂)₂IC₆H₅ in CHCl₃/pyridine⁵⁰ to furnish free base porphyrin8 in 82% yield. Zinc insertion afforded Zn8 in 75% yield. Porphyrin Zn8was then subjected to a Stille cross-coupling reaction⁵¹ with(vinyl)tributyltin and Pd(PPh₃)₄ to afford vinylporphyrin Zn10 in 77%yield.

3. Attachment Methods. Baking. The initial high-temperature attachmentprocedure involved a direct deposition approach. In this procedure, theporphyrin was first dissolved in an organic solvent and a small drop (1μL) of the resulting dilute solution was placed onto a micron-size Simicroelectrode that was contained in a sealed vial maintained underinert atmosphere (see Experimental Section for additional details). Thevial was then placed on a hot plate preheated to a particulartemperature and the system was “baked” for a specified time. The Siplatform was then cooled, washed to remove non-attached porphyrin, andinterrogated voltammetrically to investigate the quality of themonolayer and determine the surface coverage (by integration of thepeaks in the voltammogram).

The “best” attachment conditions for direct deposition were determinedvia a systematic study using porphyrins Zn1 and Zn7 that probed theeffects of varying the baking temperature, the baking time, theconcentration of the porphyrins in the deposition solution, and thenature of the deposition solvent. The first three of these variables arenot independent; however, the studies revealed the following generaltrends: (1) As the baking temperature is increased, the surface coveragemonotonically increases. For example, increasing the baking temperaturefrom 100 to 400° C. (baking time 30 min; deposition solution porphyrinconc. 1 mM) increased the surface concentration from 1×10⁻¹¹ mol cm⁻² to˜8×10⁻¹¹ mol cm⁻² (the saturating coverage for the porphyrin is ˜10⁻¹⁰mol cm⁻²). At temperatures above 400° C., no further attachment isachieved and the system degrades. (2) As the baking temperature isincreased, the time required to achieve the highest surface coveragemonotonically decreases. For example, a baking time of 1 h was requiredto achieve maximum coverage at 200° C. This time was reduced to 2 minwhen the baking temperature was elevated to 400° C. (3) As theconcentration of the porphyrin in the deposition solution was increasedfrom 1 μM to 100 μM, the surface coverage for a given baking time andtemperature systematically increased. Increasing the porphyrinconcentrations above 100 μM had little effect on the coverage. (4) Bothhigh-boiling (benzonitrile, bp=191° C.) and low-boiling (THF, bp=66° C.)solvents yielded essentially identical results for a particular set ofdeposition and baking conditions. The best conditions were applied toseveral porphyrins. FIG. 1 (top panels) shows representative cyclicvoltammograms of Zn1 and Zn7 obtained by attaching the porphyrins usinga 100 μM deposition solution followed by baking at 400° C. for 2 min.

Sublimation. The next high-temperature attachment procedure involved anindirect deposition approach. In this procedure, a small quantity of theporphyrin (<1 mg) was placed in the bottom of a cylindrical glasscontainer whose diameter permitted insertion into the heating vial. Thetop of the container was flat to allow the Si platform to be placed ontop with the micron-size electrode facing downward (˜3 mm above thesolid sample). The vial was sealed, purged with Ar, placed on a hotplate preheated to a particular temperature, and the porphyrin wassublimed for a specified time. The Si platform was then cooled, washedto remove non-attached porphyrin, and interrogated voltammetrically toinvestigate the quality of the monolayer and determine the surfacecoverage. Representative cyclic voltammograms of Zn1 and Zn7 are shownin FIG. 1 (bottom panels). Both of these molecules were attached bysubliming at 400° C. for 20 min. The “best” attachment conditions forindirect deposition were determined via a systematic study that probedthe effects of varying the sublimation temperature and baking time. Attemperatures below 300° C., relatively little attachment was achievedvia the sublimation method. At 400° C., the surface coveragemonotonically increased as the sublimation time was increased. Nofurther coverage was observed for times longer than 20 min. It isnoteworthy that while sublimation of porphyrinic compounds is awell-known process for purification and for generation of thin films,⁵⁶the sublimation process developed herein employs porphyrins bearing areactive tether and enables fabrication of surface-attached monolayersof the porphyrins.

Scope of Application. With the baking and sublimation methods in handfor attachment of porphyrins to Si, porphyrins Zn1-Zn19 were examinedfor attachment using the same deposition conditions (baking temperature400° C.; baking time 2 min; deposition solution porphyrin conc. 1 mM).The functional groups that afforded attachment include2-(trimethylsilyl)ethynyl, vinyl, allyl, and 3-butenyl directly appendedto the porphyrin, and iodo, bromomethyl, 2-(trimethylsilyl)ethynyl,ethynyl, vinyl, and allyl appended to the 4-position of a meso-phenylring. The surface coverage varied somewhat as a function of porphyrinand/or linker type; however the surface coverages were typically in therange 4×10⁻¹¹ mole cm⁻² to 8×10⁻¹¹ mol cm⁻². Attachment was not achievedfor Zn8. In general, the surface coverages and characteristic featuresof the voltammograms obtained via the sublimation method (sublimationtemperature 400° C.; sublimation time 20 min) are quite similar to thoseobtained via the baking method, indicating covalent attachment androbust electrochemical behavior.⁶ The relatively narrow voltammetricwaves and the absence of visible surface oxidation at high potentialssuggest that the porphyrins are packed relatively uniformly and fullycover the surface. As controls, the zinc chelates of various porphyrinsthat lack functional groups were examined, including2,3,7,8,12,13,17,18-octaethylporphyrin, meso-tetraphenylporphyrin,meso-tetra-p-tolylporphyrin, and meso-tetramesitylporphyrin. Noattachment was observed for any of these porphyrins as was evident fromthe observation that the baked film was completely removed by washing(in addition, no voltammetric peaks were observed). Collectively, theseresults indicate that the high-temperature attachment procedure (1) hasbroad scope encompassing diverse functional groups, (2) tolerates avariety of arene substituents, and (3) does not afford indiscriminateattachment. Finally, the Zn7 monolayer was used in an initial series oftests to evaluate the robustness to electrochemical cycling of thecarbosilane tethered porphyrins. This test was conducted as described inref 4 and showed that the voltammetric characteristics of the monolayerwere unchanged after ˜10¹⁰ redox cycles.

Outlook. We have prepared a set of porphyrins bearing carbon tethers forattachment to Si(100). Collectively, the studies reported hereinindicate that porphyrins bearing a variety of functional groups can becovalently attached to Si via high-temperature processing. The bakingand sublimation methods are complementary and together afford a nearlyuniversal strategy for attaching porphyrins. The baking method employsthe porphyrin in a dilute solution (1 μM-1 mM) while the sublimationmethod employs the porphyrin as a neat solid. We note that the successof both approaches apparently does not depend on melting the porphyrins.Indeed, the melting points of the porphyrins ranged from 230° C. (Zn19)to 435° C. (Zn14) yet good quality monolayers were obtained regardlessof melting point value. The baking approach is essentially “dry”inasmuch as only a small amount of solvent is used in the attachmentprocess; the sublimation approach is totally “dry” in that no solventsare required in the process. This latter process is particularlyappealing from a semiconductor processing perspective, wherein uniformattachment of molecules to very large (30 cm) Si wafers might beanticipated in the manufacture of future-generation hybridmolecular/semiconductor devices.

Experimental Section

A. Electrochemical Studies and Attachment Procedure. The porphyrins wereattached to Si microelectrodes (100 μm×100 μm) that were preparedphotolithographically from device-grade wafers (B-doped Si(100);ρ=0.005-0.1 Ω cm). The procedure for preparing these microelectrodes isdescribed in detail in ref 6. The electrochemical procedures,techniques, and instrumentation were also the same as described in ref6. The surface coverage of the molecules was determined by integratingthe peaks in the voltammogram. The temperature of the Si platform wasmeasured by attaching a thermocouple directly to the platform.

The basic procedures for attachment via the baking and sublimationmethods are as described in the Results and Discussion. Additionaldetails of these procedures are described below.

For the baking procedure, porphyrin concentrations in the range 1 μM to3 mM were investigated. The solvents included benzonitrile, THF, andCH₂Cl₂. The choice of solvent was primarily dictated by solubility ofthe porphyrin rather than any specific characteristics of the solvent.However, monolayers prepared using benzonitrile or THF exhibitedsuperior voltammetric characteristics relative to those prepared usingCH₂Cl₂, likely due to the fact that the halogenated solvent can reactwith the surface at high temperature.

Prior to introduction of the porphyrin and baking, the Si microelectrodewas placed in a vial. The vial was sealed with a teflon cap and purgedwith Ar for 15 min. A syringe containing the porphyrin solution wasinserted through the teflon cap and a drop of the solution was placedonto the microelectrode. The solvent was then allowed to dry under thecontinued Ar purge. The purge was stopped, the vial was transferred tothe hot plate at the preset temperature, and the electrode was baked fora specified time. The temperatures investigated ranged from 200 to 450°C.; the times ranged from 2 to 30 min. The vial was then removed fromthe hot plate and the Ar purge was reinitiated. After the vial hadreached room temperature, solvent was syringed into the vial to wash theelectrode and remove non-attached porphyrin. In some cases, themicroelectrode was removed from the vial and washed in air. Nodifference was observed in the voltammetric characteristics of themonolayers for electrodes washed under inert versus ambient conditions.

For the sublimation procedure, the vessel containing the solid porphyrinwas placed into the vial, the microelectrode was placed on top of thevessel, and the vial was sealed. The vial was then purged gently (toprevent displacing the microelectrode from the vessel) for 15 min. Thepurge was stopped and the vial was transferred to the hot plate at thepreset temperature for a specific time. Times in the range 2 to 20 minwere investigated. The vial was then removed from the hot plate andallowed to cool to room temperature. The microelectrode was then removedand washed to remove non-attached porphyrin.

B. Compound Synthesis.

General. ¹H (300 or 400 MHz) and ¹³C (75 MHz) NMR spectra were recordedin CDCl₃ unless noted otherwise. Mass spectra of porphyrins wereobtained by laser desorption mass spectrometry in the absence of amatrix (LDMS) and by high-resolution fast atom bombardment massspectrometry (FABMS). Absorption and emission spectra were collected intoluene at room temperature. Elemental analyses were performed byAtlantic Microlab, Inc. Melting points are uncorrected. For porphyrins,a melting point onset value is given. Silica gel (Baker 40 μm averageparticle size) was used for column chromatography. Chloroform contained0.8% ethanol as a stabilizer. The presence of ethanol in chloroformenables BF₃-ethanol cocatalysis in reactions with mesitaldehyde andpyrrole. The citations in the following sections refer to those listedin the body of the paper.

Melting Point Study. Each porphyrin was subjected to a melting-pointdetermination. In a few cases, relatively sharp melting points (ΔT=5-6°C.) were observed. In most cases, the mp range was partially obscured(owing to concurrent sublimation and the intense optical density of thesample). For consistency, the value for the mp onset of each compound isreported. The mp onset values are as follows: Zn1 (275° C.); Zn2 (285°C.); Zn3 (dec. at 400° C.); Zn4 (260 ° C.); Zn5 (245° C.); Zn6 (270°C.); Zn7 (255° C.); Zn8 (425° C.); Zn9 (380° C.); Zn10 (370° C.); Zn11(350° C.); Zn12 (350° C.); Zn13 (430° C.); Zn14 (435° C.); Zn15 (340°C.); Zn16 (250° C.); Zn17 (335° C.); Zn18 (290° C.); Zn19 (230° C.);Zn40 (>300° C.); Zn41 (310° C.); 45 (>450° C.).

Noncommercial Compounds. Compounds Zn1,⁶ Zn2,²⁹ Zn3,³⁰ Zn4,³¹ Zn5,³²22,³⁷ 2,4,6-triethylbenzaldehyde,⁴⁴ 26,⁴³ 29,⁴¹ 30,⁴² 32,⁴⁸ 36, ^(41,49)38,⁵² and 44⁵⁵ were prepared as described in the literature.

Zn(II)-5,10,15-Trimesityl-5-(4-vinylphenyl)porphyrin (Zn6). Following astandard procedure for mixed-aldehyde condensation³⁴ at highconcentration³⁵ with BF₃.O(Et)₂-ethanol cocatalysis,³⁶ samples of 21(500 mg, 2.81 mmol), mesitaldehyde (1.24 mL, 8.42 mmol), and pyrrole(779 μL, 11.2 mmol) were condensed in CHCl₃ (153 mL) in the presence ofBF₃.O(Et)₂ (347 μL, 2.74 mmol) at room temperature for 1 h. Then DDQ(1.91 g, 8.42 mmol) was added. After 10 min, the crude mixture waspassed through a silica column (CH₂Cl₂) to recover the mixture ofporphyrins free from polar byproducts. A solution of the porphyrinmixture in CHCl₃ (150 mL) was treated with a solution of Zn(OAc)₂.2H₂O(1.53 g, 7.00 mmol) in MeOH (20 mL). After 15 h, the solution was washedwith water. Column chromatography [silica, CHCl₃/hexanes (11:9) followedby silica, CHCl₃/hexanes (1:2)] afforded a purple solid (330 mg, 14%):mp onset 270° C.; ¹H NMR δ 1.85 (s, 12H), 1.87 (s, 6H), 2.63 (s, 9H),5.48 (d, J=10.0 Hz, 1H), 6.08 (d, J=16.8 Hz, 1H), 7.07 (dd, J¹=16.8 Hz,J²=10.0 Hz, 1H), 7.31 (s, 6H), 7.82 (d, J=9.6 Hz, 2H), 8.21 (d, J=9.6Hz, 2H), 8.70-8.79 (m, 6H), 8.92 (d, J=5.4 Hz, 2H); LDMS obsd 829.4;FABMS obsd 828.3176, calcd 828.3170 (C₅₅H₄₈N₄Zn); λ_(abs) 423, 512, 550,588 nm.

Zn(II)-5-(4-Allylphenyl)-10,15,20-trimesitylporphyrin (Zn7). Followingthe procedure for Zn6, reaction of 23 (365 mg, 2.50 mmol), mesitaldehyde(1.11 g, 7.50 mmol), and pyrrole (672 mg, 10.0 mmol) was carried out inCHCl₃ (1.0 L) in the presence of BF₃.O(Et)₂ (1.32 mL of a 2.5 M solutionin CHCl₃) at room temperature for 1 h followed by oxidation with DDQ(1.70 g, 7.50 mmol) and passage through a silica pad [CH₂Cl₂/hexanes,(1:1)]. The mixture of porphyrins was dissolved in THF (250 mL) andtreated with Zn(OAc)₂.2H₂O (450 mg, 2.10 mmol) at 50° C. for 4 h andthen overnight at room temperature. The volume of THF was reduced to 50mL and the mixture of zinc porphyrins was precipitated upon addition ofmethanol. Chromatography [silica, toluene/hexanes, (1:2.5)] followed bycrystallization (CH₂Cl₂/MeOH) gave pink crystals (250 mg, 12%): mp onset255° C.; ¹H NMR δ 1.83 (s, 18H), 2.63 (s, 9H), 3.75 (d, J=6.4 Hz 2H),5.30 (m, 2H), 6.29-6.32 (m, 1H), 7.26 (s, 6H), 7.55 (d, J=7.2 Hz, 2H),8.13 (d, J=8.0 Hz, 2H), 8.69 (s, 4H), 8.73 (d, J=4.8 Hz, 2H), 8.87 (d,J=4.8 Hz, 2H); LDMS obsd 842.97; FABMS obsd 842.3365, calcd 842.3327(C₅₆H₅₀N₄Zn); λ_(abs) 421, 551, 593 nm.

5-Iodo-10,15,20-tri-p-tolylporphyrin (8). Following a standard method,⁵⁰a solution of 37 (871 mg, 1.50 mmol) and I₂ (267 mg, 1.05 mmol) in CHCl₃(210 mL) was treated with a solution of[bis(trifluoroacetoxy)iodo]benzene (478 mg, 1.20 mmol) in CHCl₃ (30 mL)followed by pyridine (1.3 mL). The mixture was stirred at roomtemperature for 1 h. The reaction mixture was diluted with CH₂Cl₂,washed with aqueous Na₂S₂O₃, water and dried (Na₂SO₄). Afterconcentrating the solution to a volume of ˜100 mL, 30 mL of hexanes wasadded. The resulting purple precipitate was filtered, washed (CH₂Cl₂,hexanes) and dried to yield the free base porphyrin (618 mg). Thefiltrate was concentrated and chromatographed (silica gel, warmtoluene/hexanes=7:3), affording additional free base porphyrin (253 mg).The total yield is 871 mg (82%): ¹H NMR δ −2.70 (s, 2H), 2.69-2.74 (brs,9H), 7.53-7.59 (br m, 6H), 8.04-8.09 (br m, 6H), 8.78-8.83 (m, 4H), 8.89(d, J=4.8 Hz, 2H), 9.67 (d, J=4.4 Hz, 2H); LDMS obsd 706.9; FABMS obsd706.1613, calcd 706.1593 (C₄₁H₃₁IN₄); λ_(abs) 424, 520, 557, 598, 656nm.

Zn(II)-5-Iodo-10,15,20-tri-p-tolylporphyrin (Zn8). A solution of 8 (353mg, 0.500 mmol) in THF (60 mL) was treated with Zn(OAc)₂.2H₂O (1.10 g,5.00 mmol) at room temperature for 8 h. After removal of the solvent,the residue was chromatographed (silica gel, hexanes/CH₂Cl₂, (1:1)]affording a powder that was recrystallized [(hexanes/CH₂Cl₂), 349 mg,91%]: mp onset 425° C.; ¹H NMR δ 2.67-2.70 (br s, 9H), 7.53-7.59 (br m,6H), 8.01-8.06 (br m, 6H), 8.79 (m, 4H), 8.87 (d, J=5.6 Hz, 2H), 9.72(d, J=4.4 Hz, 2H); LDMS obsd 770.5; FABMS obsd 768.0760, calcd 768.0728(C₄₁H₂₉IN₄Zn); λ_(abs) 429, 519, 556, 596 nm.

Zn(II)-5-[2-(Trimethylsilyl)ethynyl]-10,15,20-tri-p-tolylporphyrin(Zn9). A sample of 32 (473 mg, 1.00 mmol) was reduced following ageneral procedure³⁹ and the resulting 32-diol was condensed with 26 (243mg, 1.00 mmol) in CH₃CN (400 mL) under TFA (930 μL, 12.1 mmol) catalysisat room temperature for 4 min. Then DDQ (681 mg, 3.00 mmol) was added.After 1 h, TEA (2 mL) was added. The mixture was concentrated and theresidue was chromatographed [silica gel, hexanes/CH₂Cl₂, (3:7)]affording the free base porphyrin (116 mg, 17%): mp onset 380° C.; ¹HNMR δ −2.41 (s, 2H), 0.62 (s, 9H), 2.71 (s, 3H), 2.72 (s, 6H), 7.54 (d,J=8.0 Hz, 2H), 7.57 (d, J=8.0 Hz, 4H), 8.05 (d, J=8.0 Hz, 2H), 8.08 (d,J=8.0 Hz, 4H), 8.79 (s, 4H), 8.92 (d, J=4.4 Hz, 2H), 9.65 (d, J=4.8 Hz,2H); LDMS obsd 676.2; FABMS obsd 676.3047, calcd 676.3022 (C₄₆H₄₀N₄Si);λ_(abs) 431, 497, 529, 567, 606, 664 nm. A sample of the free baseporphyrin (169 mg, 0.250 mmol) in THF (25 mL) was treated with asolution of Zn(OAc)₂.2H₂O (275 mg, 1.25 mmol) in MeOH (2 mL) at roomtemperature for 12 h. Column chromatography [hexanes/CH₂Cl₂, (3:7)]afforded a purple solid (136 mg, 74%; 13% overall yield): ¹H NMR δ 0.62(s, 9H), 2.70-2.73 (br s, 9H), 7.53-7.59 (m, 6H), 8.04-8.10 (m, 6H),8.79 (s, 4H), 8.92 (m, 2H), 9.65 (m, 2H); LDMS obsd 739.8; FABMS obsd738.2167, calcd 738.2157 (C₄₆H₃₈N₄SiZn); λ_(abs) 434, 523, 563, 605 nm.

Zn(II)-5,10,15-Tri-p-tolyl-20-vinylporphyrin (Zn10). A solution of Zn8(50 mg, 60 μmol) in THF (24 mL) was treated overnight with Pd(PPh₃)₄ (7mg) and tributyl(vinyl)tin (190 μL, 600 μmol) at 60° C. under argon. Thereaction mixture was concentrated. Column chromatography [silica,CH₂Cl₂/hexanes (1:1)] followed by trituration of the product withhexanes afforded a purple solid (34 mg, 77%): mp onset 370° C.; ¹H NMR δ2.72 (s, 3H), 2.74 (s, 6H), 6.05 (d, J=17.6 Hz, 1H), 6.49 (d, J=11.6 Hz,1H), 7.55-7.58 (m, 6H), 8.08-8.10 (m, 6H), 8.95 (s, 4H), 8.99 (d, J=4.4Hz, 2H), 9.16-9.23 (m, 1H), 9.51 (d, J=4.4 Hz, 2H); LDMS obsd 668.8;FABMS obsd 668.1928, calcd 668.1918 (C₄₃H₃₂N₄Zn); λ_(abs) 426, 554, 595nm.

Zn(II)-5-Allyl-10,15,20-tri-p-tolylporphyrin (Zn11). A sample of32-SnBu₂ (500 mg, 0.711 mmol) was reduced following a generalprocedure³⁹ and the resulting 32-diol was condensed with 24 (132 mg,0.711 mmol) in CH₂Cl₂ (264 mL) containing Yb(OTf)₃ (564 mg, 0.910 mmol)at room temperature for 7 min. Then DDQ (3 equiv per dipyrromethane; 484mg, 2.13 mmol) was added. The reaction mixture was passed over a silicacolumn (CH₂Cl₂). The resulting free base porphyrin was dissolved inCHCl₃ (50 mL) and treated with a solution of Zn(OAc)₂.2H₂O (780 mg, 3.6mmol) in MeOH (7 mL) at room temperature for 2 h. Column chromatography(silica, CHCl₃) afforded a purple solid (207 mg, 42%): mp onset 350° C.;¹H NMR δ 2.71 (s, 3H), 2.73 (s, 6H), 5.18-5.22 (m, 2H), 5.77 (d, 2H),6.88 (m, 1H), 7.53-7.57 (m, 6H), 8.07-8.10 (m, 6H), 8.92 (s, 4H), 9.00(d, J=4.4 Hz, 2H), 9.53 (d, J=4.4 Hz, 2H); LDMS obsd 681.3; FABMS obsd682.2084, calcd 682.2075 (C₄₄H₃₄N₄Zn); λ_(abs) 424, 552, 592 nm.

Zn(II)-5-(3-Butenyl)-10,15,20-tri-p-tolylporphyrin (Zn12). Following theprocedure for Zn11, the condensation of 32-diol (derived from 32-SnBu₂;500 mg, 0.711 mmol) and 25 (142 mg, 0.711 mmol) for 7 min, oxidationwith DDQ, passage through a silica pad (CH₂Cl₂), and metalation withZn(OAc)₂.2H₂O followed by chromatography (silica, CHCl₃) afforded apurple solid (213 mg, 44%): mp onset 300° C.; ¹H NMR δ 2.71 (s, 3H),2.73 (s, 6H), 3.32 (m, 2H), 5.07-5.17 (m, 3H), 5.77 (d, 1H), 6.29 (m,1H), 7.54-7.58 (m, 6H), 8.07-8.10 (m, 6H), 8.92 (s, 4H), 9.01 (d, J=4.4Hz, 2H), 9.52 (d, J=4.4 Hz, 2H); LDMS obsd 697.1, 656.0 [(M-allyl)⁺];FABMS obsd 696.2203, calcd 696.2231 (C₄₅H₃₆N₄Zn); λ_(abs) 424, 513, 552,591 nm.

Zn(II)-5,10,15-Tri-p-tolyl-20-(4-vinylphenyl)porphyrin (Zn13). Followingthe procedure for Zn9, the reaction of 32-diol (derived from 32; 600 mg,1.27 mmol) and 27 (315 mg, 1.27 mmol) in MeCN (508 mL) containing TFA(1.17 mL, 15.2 mmol) for 3 min followed by oxidation with DDQ (865 mg,3.81 mmol), neutralization with TEA (1 mL), and passage through a silicapad (CH₂Cl₂) afforded the partially purified free base porphyrin.Metalation in CHCl₃ (150 mL) with Zn(OAc)₂.2H₂O (640 mg, 2.92 mmol) inMeOH (15 mL) for 1 h and the standard workup including washing with MeOHfurnished a purple solid (242 mg, 26%): mp onset 430° C.; ¹H NMR δ 2.67(s, 9H), 5.48 (d, J=10.0 Hz, 1H), 6.11 (d, J=16.8 Hz, 1H), 7.10 (dd,J¹=16.8 Hz, J²=10.0 Hz, 1H), 7.60 (d, J=8.4 Hz, 6H), 7.82 (d, J=8.4 Hz,2H), 8.11 (d, J=8.4 Hz, 6H), 8.21 (d, J=8.4 Hz, 2H), 8.99-9.01 (m, 8H);LDMS obsd 745.2; FABMS obsd 744.2233, calcd 744.2231 (C₄₉H₃₆N₄Zn);λ_(abs) 425, 551, 592 nm.

Zn(II)-5-(4-Allylphenyl)-10,15,20-tri-p-tolylporphyrin (Zn14). Followingthe procedure for Zn11, the condensation of 32-diol (derived from32-SnBu₂; 2.00 g, 2.84 mmol) and 28 (745 mg, 2.84 mmol) for 15 min,oxidation with DDQ (1.93 g, 8.52 mmol) and passage through a silica pad(CH₂Cl₂) afforded the free base porphyrin, which was suspended inethanol/hexanes (1:1), sonicated for 5 min and then centrifuged. Theethanol/hexanes mixture was decanted and the solid was dried affordingthe free base porphyrin (14) (455 mg, 23%): mp onset 435° C.; ¹H NMRδ−2.77 (brs, 2H), 2.71 (s, 9H), 3.75 (d, J=7.8 Hz, 2H), 5.27-5.37 (m,2H), 6.26-6.33 (m, 1H), 7.55-7.58 (m, 8H), 8.10-8.16 (m, 8H), 8.86 (s,8H); LDMS obsd 697.4; FABMS obsd 696.3265, calcd 696.3253 (C₅₀H₄₀N₄).Metalation of the free base porphyrin (100 mg, 0.143 mmol) in CHCl₃ (15mL) with Zn(OAc)₂.2H₂O (157 mg, 0.717 mmol) in MeOH (2 mL) for 18 hfollowed by standard workup and chromatography (silica, CHCl₃) affordeda purple solid (106 mg, 97%): ¹H NMR δ 2.72 (s, 9H), 3.76 (d, J=7.8 Hz,2H), 5.27-5.38 (m, 2H), 6.25-6.35 (m, 1H), 7.55-7.58 (m, 8H), 8.10 (d,J=7.6 Hz, 6H), 8.14 (d, J=8.0 Hz, 2H), 8.97 (s, 8H); LDMS obsd 759.4;FABMS obsd 758.2429, calcd 758.2388 (C₅₀H₃₈N₄Zn); λ_(abs) 424, 511, 550,591 nm.

Zn(II)-5-(4-Allylphenyl)-15-mesityl-10,20-di-p-tolylporphyrin (Zn15).Following the procedure for Zn11, the condensation of 33-diol (derivedfrom 33-SnBu₂; 699 mg, 0.953 mmol) and 28 (250 mg, 0.953 mmol) for 15min, oxidation with DDQ (649 mg, 2.86 mmol), passage through a silicapad (CH₂Cl₂), and metalation with Zn(OAc)₂.2H₂O followed bychromatography (silica, CHCl₃) afforded a purple solid (161 mg, 21%): mponset 340° C.; ¹H NMR δ 1.85 (s, 6H), 2.64 (s, 3H), 2.71 (s, 6H), 3.76(d, J=6.8 Hz, 2H), 5.27-5.37 (m, 2H), 6.29 (m, 1H), 7.29 (s, 2H),7.55-7.58 (m, 6H), 8.11-8.16 (m, 6H), 8.79 (d, J=4.8 Hz, 2H), 8.92 (d,J=4.8 Hz, 2H), 8.96 (s, 4H); LDMS obsd 828.5, 845.5; FABMS obsd828.3151, calcd 828.3170 (C₅₅H₄₈N₄Zn). λ_(abs) 425, 485, 513, 551, 592nm.

Zn(II)-5-(4-Allylphenyl)-10,20-di-p-tolyl-15-(2,4,6-triethylphenyl)porphyrin(Zn16). Following the procedure for Zn11, the condensation of 34-diol(derived from 34-SnBu₂; 483 mg, 0.625 mmol) and 28 (163 mg, 0.625 mmol)for 30 min, oxidation with DDQ, passage through a silica pad (CH₂Cl₂),metalation with Zn(OAc)₂.2H₂O, and chromatography (silica, CHCl₃)afforded a purple solid (51 mg, 10%): mp onset 250° C.; ¹H NMR δ 0.74(t, J=7.2 Hz, 6H), 1.54 (t, J=7.4 Hz, 3H), 2.09 (q, 4H), 2.72 (s, 6H),3.00 (q, 2H), 3.76 (d, J=6.6 Hz, 2H), 5.27-5.38 (m, 2H), 6.26-6.35 (m,1H), 7.35 (s, 2H), 7.54-7.59 (m, 6H), 8.12-8.17 (m, 6H), 8.80 (d, J=4.5Hz, 2H), 8.92 (d, J=4.5 Hz, 2H), 8.97 (s, 4H); LDMS obsd 828.5; FABMSobsd 828.3151, calcd 828.3170 (C₅₅H₄₈N₄Zn); λ_(abs) 425, 513, 551, 592nm.

Zn(II)-5-(4-Allylphenyl)-10,20-dimethyl-15-p-tolylporphyrin (Zn17).Following the procedure for Zn11, the condensation of 35-diol (derivedfrom 35-SnBu₂; 427 mg, 0.740 mmol) and 29 (175 mg, 0.741 mmol) for 30min, oxidation with DDQ, passage through a silica pad (CH₂Cl₂), andmetalation with Zn(OAc)₂.2H₂O followed by chromatography (silica, CHCl₃)afforded a purple solid (69 mg, 15%): mp onset 335° C.; ¹H NMR δ 2.73(s, 3H), 3.77 (d, J=6.6 Hz, 2H), 4.67 (s, 6H), 5.29-5.40 (m, 2H),6.25-6.39 (m, 1H), 7.56-7.60 (m, 4H), 8.07-8.14 (m, 4H), 8.98-9.00 (m,4H), 9.56 (d, J=4.5 Hz, 4H); LDMS obsd 605.3; FABMS obsd 606.1798, calcd606.1762 (C₃₈H₃₀N₄Zn); λ_(abs) 425, 515, 554, 597 nm.

Zn(II)-5-(4-Allylphenyl)-15-mesityl-10,20-dimethylporphyrin (Zn18).Following the procedure for Zn11, the condensation of 35-diol (derivedfrom 35-SnBu₂; 427 mg, 0.740 mmol) and 30 (196 mg, 0.740 mmol) for 30min, oxidation with DDQ, passage through a silica pad (CH₂Cl₂), andmetalation with Zn(OAc)₂.2H₂O followed by chromatography (silica, CHCl₃)afforded a purple solid (90 mg, 19%): mp onset 290° C.; ¹HNMR δ 1.83 (s,6H), 2.66 (s, 3H), 3.77 (d, J=6.6 Hz, 2H), 4.66 (s, 6H), 5.29-5.40 (m,2H), 6.25-6.39 (m, 1H), 7.30 (s, 2H), 7.58 (d, J=7.8 Hz, 2H), 8.11 (d,J=7.8 Hz, 2H), 8.82 (d, J=4.5 Hz, 2H), 8.95 (d, J=4.5 Hz, 2H), 9.53 (d,J=4.5 Hz, 4H); LDMS obsd 634.4; FABMS obsd 634.2120, calcd 634.2075(C₄₀H₃₄N₄Zn); λ_(abs) 424, 515, 553, 597 nm.

Zn(II)-5-(4-Allylphenyl)-10,20-dimethyl-15-(2,4,6-triethylphenyl)porphyrin(Zn19). Following the procedure for Zn11, the condensation of 35-diol(derived from 35-SnBu₂; 427 mg, 0.740 mmol) and 31 (227 mg, 0.740 mmol)for 25 min, oxidation with DDQ, passage through a silica pad (CH₂Cl₂),and metalation with Zn(OAc)₂.2H₂O followed by chromatography [silica,CHCl₃/hexanes (1:1)] afforded a purple solid (45 mg, 9%): mp onset 230°C.; ¹HNMR δ 0.71 (t, J=7.5 Hz, 6H), 1.56 (t, J=7.5 Hz, 3H) 2.10 (q. 4H),2.99 (q, 2H), 3.77 (d, J=6.6 Hz, 2H), 4.66 (s, 6H), 5.29-5.40 (m, 2H),6.25-6.39 (m, 1H), 7.34 (s, 2H), 7.58 (d, J=7.8 Hz, 2H), 8.11 (d, J=7.8Hz, 2H), 8.82 (d, J=4.5 Hz, 2H), 8.95 (d, J=4.5 Hz, 2H), 9.50 (d, J=4.5Hz, 2H), 9.54 (d, J=4.5 Hz, 2H); LDMS obsd 676.4; FABMS obsd 676.2580,calcd 676.2544 (C₄₃H₄₀N₄Zn); λ_(abs) 425, 515, 554, 597 nm.

1-Iodo-4-(1,1-dimethoxymethyl)benzene (20). A solution of4-iodobenzaldehyde (10.0 g, 43.1 mmol) in MeOH (150 mL) was treated withTiCl₄ (80 μL, 430 μmol) under argon for 15 min. TEA (0.2 mL) was added.After 15 min, water and Et₂O were added. The organic layer wascollected, dried (Na₂SO₄), filtered, and concentrated to give a paleyellow oil (11.5 g, 96%): ¹H NMR δ 3.30 (s, 6H), 5.34 (s, 1H), 7.19 (d,J=8.4 Hz, 2H), 7.70 (d, J=8.4 Hz, 2H); ¹³C NMR δ 52.4, 94.3, 102.1,128.6, 137.1, 137.6.

1-(1,1-Dimethoxymethyl)-4-vinylbenzene (21). A sample of 20 (8.50 g,30.6 mmol) was treated with vinylmagnesium bromide (33.6 mL, 33.6 mmol,1.0 M solution in THF) followed by Pd(PPh₃)₂Cl₂ (220 mg, 1 mol %). Themixture was stirred at room temperature under argon for 2 h. Water andEt₂O were added. The aqueous layer was washed with Et₂O. The organiclayer was collected, dried (Na₂SO₄), filtered, and concentrated.Chromatography [silica, Et₂O/hexanes/TEA (25:75:1)] afforded a colorlessoil (3.51 g, 64%): ¹H NMR δ 3.33 (s, 6H), 5.25 (d, J=10.0 Hz, 1H), 5.39(s, 1H), 5.75 (d, J=16.8 Hz, 1H), 6.72 (dd, J¹=16.8 Hz, J²=10.0 Hz, 1H),7.41 (s, 4H); ¹³C NMR δ 52.3, 102.6, 113.9, 125.9, 126.5, 126.8, 128.0,136.3, 137.4, 137.5; FABMS obsd 178.0944, calcd 178.0994 (C₁₁H₁₄O₂).

4-Allylbenzaldehyde (23). Following a standard procedure,³⁸ a solutionof 22 (2.36 g, 10.2 mmol) in CH₂Cl₂ (60 mL) was treated with TFA (12 mL)and water (0.3 mL). The solution was stirred for 18 h. Then aqueousNaHCO₃ (5%, 150 mL) was added. The organic phase was washed with aqueousNaHCO₃ and brine, then dried (Na₂SO₄) and concentrated. Chromatography(silica, CH₂Cl₂/hexanes, 1:2) afforded a colorless oil that partiallysolidified after standing at 0° C. for a few weeks (1.20 g, 81%): ¹H NMRδ 3.47 (d, J=6.4 Hz 2H), 5.09-5.15 (m, 2H), 5.92-5.99 (m, 1H), 7.36 (d,J=8.4 Hz, 2H), 7.82 (d, J=8.0 Hz, 2H), 9.81 (s, 1H); ¹³C NMR 40.1,116.7, 129.1, 129.8, 134.5, 135.9, 147.2, 191.7; FABMS obsd 146.0739,calcd 146.0732 (C₁₀H₁₀O).

5-Allyldipyrromethane (24). Following a standard procedure,^(40,41) asolution of 3-butenal diethylacetal (4.00 g, 27.7 mmol) in pyrrole (194mL, 2.77 mol) at room temperature under argon was treated with TFA (467μL, 2.77 mmol) for 10 min. TEA (221 μL, 2.77 mmol) was added. Themixture was concentrated under high vacuum. The residue waschromatographed [silica, hexanes/ethyl acetate (4:1)] to afford a paleorange oil (1.85 g, 36%): ¹H NMR δ 2.86 (t, J=8.0 Hz, 2H), 4.11 (t,J=8.0 Hz, 1H), 5.02-5.12 (m, 2H), 5.83 (m, 1H), 6.08 (s, 2H), 6.15 (m,2H), 6.65 (m, 2H), 7.83 (br s, 2H); ¹³C NMR δ 37.3, 38.7, 105.6, 107.6,116.3, 117.1, 132.8, 136.2; FABMS obsd 187.1230, calcd 187.1235[(M+H)⁺], (M=C₁₂H₁₄N₂).

5-(3-Butenyl)dipyrromethane (25). Following a standard procedure,⁴² asolution of 4-pentenal (4.00 g, 47.6 mmol) in pyrrole (332 mL, 4.76 mol)at room temperature under argon was treated with InCl₃ (1.05 g, 4.76mmol) for 1.5 h. Powdered NaOH (5.71 g, 143 mmol) was added. Afterstirring for 30 min, the mixture was suction-filtered. The filtrate wasconcentrated under high vacuum. The resulting residue waschromatographed [silica, hexanes/ethyl acetate (4:1)] to afford a paleyellow oil (7.48 g, 78%): ¹H NMR δ 2.05 (m, 4H), 4.00 (m, 1H), 4.96-5.05(m, 2H), 5.80 (m, 1H), 6.08 (s, 2H), 6.15 (m, 2H), 6.62 (m, 2H), 7.71(br s, 2H); ¹³C NMR δ 31.3, 33.1, 36.5, 105.5, 107.6, 114.9, 117.1,133.1, 138.0; FABMS obsd 200.1321, calcd 200.1313 (C₁₃H₁₆N₂).

5-(4-Vinylphenyl)dipyrromethane (27). Following the procedure for 25,the reaction of 21 (2.78 g, 15.6 mmol) in pyrrole (108 mL, 1.56 mol) andthe standard workup including chromatography (silica, CH₂Cl₂ followed bysilica, toluene) afforded a yellow solid (2.52 g, 65%): mp 75-78° C.; ¹HNMR δ(CD₂Cl₂) 5.24 (d, J=10.0 Hz, 1H), 5.44 (s, 1H), 5.75 (d, J=16.8 Hz,1H), 5.87-5.88 (m, 2H), 6.11-6.13 (m, 2H), 6.68-6.76 (m, 3H), 7.17 (d,J=8.0 Hz, 2H), 7.38 (d, J=8.0 Hz, 2H), 8.01 (brs, 2H); ¹³C NMR δ(CD₂Cl₂) 44.2, 107.5, 108.8, 114.1, 117.8, 126.9, 129.0, 133.0, 136.8,136.9, 142.6; FABMS obsd 248.1311, calcd 248.1313; Anal. Calcd forC₁₇H₁₆N₂: C, 82.22; H, 6.49; N, 11.28; Found: C, 82.44; H, 6.45; N,11.24.

5-(4-Allylphenyl)dipyrromethane (28). Following the procedure for 25,the reaction of 23 (1.75 g, 12.0 mmol) in pyrrole (83 mL, 1.2 mol) andthe standard workup including chromatography (silica, toluene) followedby recrystallization from EtOH/H₂O (6:1) afforded an off-white solid(1.92 g, 61%): mp 60-62° C.; ¹H NMR δ 3.37 (d, J=8.0 Hz, 2H), 5.06-5.11(m, 2H), 5.46 (s, 1H), 5.93-5.99 (m, 3H), 6.15-6.17 (m, 2H), 6.69-6.70(m, 2H), 7.15 (s, 4H), 7.91 (brs, 2H); ¹³C NMR δ 39.8, 43.6, 107.1,108.4, 115.9, 117.1, 128.4, 128.8, 132.6, 137.3, 138.8, 139.8; FABMSobsd 262.1476, calcd 262.1470; Anal. Calcd for C₁₈H₁₈N₂: C, 82.41; H,6.92; N, 10.68; Found: C, 82.44; H, 6.85; N, 10.44.

5-(2,4,6-Triethylphenyl)dipyrromethane (31). Following a standardprocedure for mesitaldehyde,⁴² a solution of 2,4,6-triethylbenzaldehyde(5.70 g, 30.0 mmol) in pyrrole (210 mL, 3.00 mol) was treated with MgBr₂(2.76 g, 15.0 mmol) at room temperature for 1 h. Powdered NaOH (6.0 g,15 mmol) was added. After stirring for 30 min, the mixture wassuction-filtered. The filtrate was concentrated under high vacuum.Chromatography (silica, CHCl₃ followed by silica, toluene) of theresidue afforded a brown oil (5.22 g, 57%): ¹H NMR δ 0.93 (brs, 6H),1.28 (t, J=8.0 Hz, 3H), 2.53 (brs, 4H), 2.64 (q, J=7.6 Hz, 2H), 5.96 (s,1H), 6.07 (s, 2H), 6.19 (m, 2H), 6.66 (s, 2H), 6.97 (s, 2H), 7.95 (brs,2H); ¹³C NMR δ 15.2, 27.0, 28.3, 37.3, 106.4, 108.3, 115.9, 127.3,131.8, 133.1, 143.1; FABMS obsd 306.2103, calcd 306.2096 (C₂₁H₂₆N₂).

Dibutyl[5,10-dihydro-1,9-di-p-toluoyl-5-p-tolyldipyrrinato]tin(IV)(32-SnBu₂). Following a general diacylation procedure,³⁹ a solution of29 (5.00 g, 21.2 mmol) in toluene (125 mL) was treated with EtMgBr (100mL, 100 mmol, 1.0 M in THF) followed by p-toluoyl chloride (7.0 mL, 53mmol). After quenching and extractive workup, the crude material wasdissolved in CH₂Cl₂ (200 mL). Samples of TEA (8.9 mL, 64 mmol) andBu₂SnCl₂ (6.44 g, 21.2 mmol) were added. After 30 min, the solution wasconcentrated. Column chromatography (silica, CH₂Cl₂) followed bycrystallization (MeOH) afforded a pale green solid (8.54 g, 57%): mp124-126° C.; ¹H NMR δ 0.69 (t, J=7.2 Hz, 3H), 0.74 (t, J=7.2 Hz, 3H),1.09-1.14 (m, 2H), 1.19-1.25 (m, 2H), 1.30-1.34 (m, 2H), 1.41-1.45 (m,2H), 1.47-1.52 (m, 2H), 1.66-1.70 (m, 2H), 2.31 (s, 3H), 2.44 (s, 6H),5.56 (s, 1H), 6.19 (d, J=4.0 Hz, 2H), 7.08-7.11 (m, 6H), 7.29 (d, J=8.0Hz, 4H), 7.82 (d, J=8.0 Hz, 4H); ¹³ C NMR δ 13.55, 13.57, 21.0, 21.5,23.9, 24.7, 25.9, 26.3, 27.16, 27.22, 45,2, 115.0, 123.7, 127.9, 129.0,129.1, 129.3, 135.0, 135.7, 136.2, 141.3, 142.0, 151.7, 184.3; FABMSobsd 705.2503, calcd 705.2525 [(M+H)⁺]; Anal. Calcd for C₄₀H₄₄N₂O₂Sn; C,68.29; H, 6.30; N, 3.98; Found: C, 68.33; H, 6.35; N, 3.92.

Dibutyl[5,10-dihydro-5-mesityl-1,9-di-p-toluoyldipyrrinato]tin(IV)(33-SnBu₂). Following the procedure for 32-SnBu₂, the reaction of 30(2.00 g, 7.57 mmol) and p-toluoyl chloride (2.00 mL, 15.1 mmol) followedby tin complexation (TEA, 3.2 mL, 23 mmol; Bu₂SnCl₂, 2.30 g, 7.57 mmol),chromatography (silica, CH₂Cl₂), and precipitation (diethyl ether/MeOH)afforded a pale yellow solid (2.87 g, 52%): mp 151-153° C.; ¹H NMR δ0.71 (t, J=7.2 Hz, 3H), 0.78 (t, J=7.2 Hz, 3H), 1.11-1.21 (m, 2H),1.21-1.36 (m, 4H), 1.43-1.55 (m, 4H), 1.70-1.78 (m, 5H), 2.32 (s, 3H),2.43 (s, 6H), 2.51 (s, 3H), 5.81 (d, J=4.0 Hz, 2H), 5.93 (s, 1H), 6.81(s, 1H), 6.98 (s, 1H), 7.04 (d, J=4.0 Hz, 2H), 7.29 (d, J=8.0 Hz, 4H),7.81 (d, J=8.0 Hz, 4H); ¹³C NMR δ 13.6, 20.3, 20.7, 20.9, 21.6, 23.5,24.9, 26.2, 26.4, 27.5, 40.0, 113.9, 123.8, 128.7, 129.0, 130.7, 135.1,135.3, 136.0, 136.3, 136.4, 138.1, 141.9, 151.9, 183.9; FABMS obsd733.2826, calcd 733.2816 [(M+H)⁺]; Anal. calcd for C₄₂H₄₈N₂O₂Sn; C,68.96; H, 6.61; N, 3.83; Found: C, 68.84; H, 6.61; N, 3.76.

Dibutyl[5,10-dihydro-5-(2,4,6-triethylphenyl)-1,9-di-p-toluoyldipyrrinato]tin(IV)(34-SnBu₂). Following the procedure for 32-SnBu₂, the reaction of 31(2.00 g, 6.52 mmol) and p-toluoyl chloride (2.16 mL, 16.3 mmol) followedby tin complexation (TEA, 2.7 mL, 20 mmol; Bu₂SnCl₂, 1.98 g, 6.52 mmol),chromatography (silica, CH₂Cl₂), and precipitation (diethyl ether/MeOH)afforded a pink solid (1.96 g, 39%): mp 136-138° C.; ¹H NMR δ 0.71-0.79(m, 9H), 1.18-1.30 (m, 12H), 1.47-1.56 (m, 4H), 1.74 (m, 2H), 2.08 (q,J=8.0 Hz, 2H), 2.43 (s, 6H), 2.66 (q, J=8.0 Hz, 2H), 2.81 (q, J=2H),5.81 (d, J=4.0 Hz, 2H), 5.88 (s, 1H), 6.93 (s, 1H), 6.98 (s, 1H), 7.01(d, J=4.0 Hz, 2H), 7.29 (d, J=8.0 Hz, 4H), 7.81 (d, J=8.0 Hz, 4H); ¹³CNMR δ 13.7, 13.8, 15.3, 16.7, 21.6, 23.5, 24.8, 25.3, 26.2, 26.5, 27.4,27.5, 28.1, 28.5, 39.4, 114.7, 123.6, 125.9, 127.1, 129.01, 129.04,135.2, 135.3, 135.4, 141.9, 142.1, 142.9, 143.9, 152.8, 183.9; FABMSobsd 775.3292, calcd 775.3286 [(M+H)⁺]; Anal. calcd for C₄₅H₅₄N₂O₂Sn; C,69.86; H, 7.04; N, 3.62; Found: C, 69.96; H, 7.00; N, 3.58.

Dibutyl[1,9-diacetyl-5-(4-allylphenyl)-5,10-dihydrodipyrrinato]tin(IV)(35-SnBu₂). Following the procedure for 32-SnBu₂, the reaction of 28(1.40 g, 5.34 mmol) and acetyl bromide (0.992 mL, 13.4 mmol) followed bytin complexation (TEA, 2.2 mL, 16 mmol; Bu₂SnCl₂, 1.62 g, 5.34 mmol),chromatography (silica, CH₂Cl₂), and precipitation (diethyl ether/MeOH)afforded a pale yellow solid (1.50 g, 57%): mp 54-56° C.; ¹H NMR δ 0.70(t, J=7.6 Hz, 3H), 0.75 (t, J=7.6 Hz, 3H), 1.05-1.57 (m, 12H), 2.41 (s,6H), 3.31 (d, J=6.8 Hz, 2H), 5.02-5.07 (m, 2H), 5.8 (s, 1H), 5.88-5.95(m, 1H), 6.10 (d, J=4.0 Hz, 2H), 7.02-7.07 (m, 6H); ¹³C NMR δ 13.49,13.52, 23.2, 23.4, 24.2, 25.9, 26.3, 27.1, 39.7, 44.8, 114.2, 115.7,120.8, 127.8, 128.0, 128.7, 136.6, 137.3, 138.2, 142.2, 150.7, 188.3;FABMS obsd 579.2036, calcd 579.2034 [(M+H)⁺]; Anal. calcd forC₃₀H₃₈N₂O₂Sn; C, 62.41; H, 6.63; N, 4.85; Found: C, 62.46; H, 6.67; N,4.86.

5,10,15-Tri-p-tolylporphyrin (37). Following the procedure for Zn11, thecondensation of 32-diol (derived from 32, 1.42 g, 3.00 mmol) and 36 (440mg, 3.01 mmol) for 20 min, oxidation with DDQ, addition of TEA (3 mL),and chromatography [silica, hexanes/CH₂Cl₂, (1:2)] afforded a purplesolid (477 mg, 27%): ¹H NMR δ −2.97 (s, 2H), 2.70-2.75 (br s, 9H), 7.56(d, J=8.0 Hz, 2H), 7.60 (d, J=8.0 Hz, 4H), 8.11 (d, J=8.0 Hz, 2H), 8.14(d, J=8.0 Hz, 4H), 8.89-8.95 (m, 4H), 9.05 (d, J=4.4 Hz, 2H), 9.33 (d,J=4.4 Hz, 2H), 10.20 (s, 1H); LDMS obsd 580.4; FABMS obsd 580.2635,calcd 580.2627 (C₄₁H₃₂N₄); λ_(abs) 414, 509, 544, 585, 641 nm.

REFERENCES

-   (1) For recent reviews, see: (a) Kwok, K. S.; Ellenbogen, J. C.    Materials Today 2002, 5, 28-37. (b) Carroll, R. L.; Gorman, C. B.    Angew. Chem. Int. Ed. 2002, 41, 4378-4400.-   (2) Roth, K. M.; Dontha, N.; Dabke, R. B.; Gryko, D. T.; Clausen,    C.; Lindsey, J. S.; Bocian, D. F.; Kuhr, W. G. J. Vac. Sci. Technol.    B 2000, 18, 2359-2364.-   (3) Li, Q.; Mathur, G.; Homsi, M.; Surthi, S.; Misra, V.;    Malinovskii, V.; Schweikart, K.-H.; Yu, L.; Lindsey, J. S.; Liu, Z.;    Dabke, R. B.; Yasseri, A.; Bocian, D. F.; Kuhr, W. G. Appl. Phys.    Lett. 2002, 81, 1494-1496.-   (4) Liu, Z.; Yasseri, A. A.; Lindsey, J. S.; Bocian, D. F. Science    2003, 302, 1543-1545.-   (5) Roth, K. M.; Liu, Z.; Gryko, D. T.; Clausen, C.; Lindsey, J. S.;    Bocian, D. F.; Kuhr, W. G. Molecules as Components of Electronic    Devices; ACS Symposium Series 844; American Chemical Society:    Washington, D.C., 2003, pp 51-61.-   (6) Roth, K. M.; Yasseri, A. A.; Liu, Z.; Dabke, R. B.; Malinovskii,    V.; Schweikart, K.-H.; Yu, L.; Tiznado, H.; Zaera, F.; Lindsey, J.    S.; Kuhr, W. G.; Bocian, D. F. J. Am. Chem. Soc. 2003, 125, 505-517.-   (7) (a) Song, J. H.; Sailor, M. J. Comments Inorg. Chem. 1999, 21,    69-84. (b) Buriak, J. M. Chem. Commun. 1999, 1051-1060. (c)    Hamers, R. J.; Coulter, S. K.; Ellison, M. D.; Hovis, J. S.;    Padowitz, D. F.; Schwartz, M. P.; Greenlief, C. M.; Russell, J. N.,    Jr. Acc. Chem. Res. 2000, 33, 617-624. (d) Buriak, J. M. Chem. Rev.    2002, 102, 1271-1308. (e) Bent, S. F. Surf. Sci. 2002, 500,    879-903. (f) Stewart, M. P.; Buriak, J. M. Comments Inorg. Chem.    2002, 23, 179-203.-   (8) Cleland, G.; Horrocks, B. R.; Houlton, A. J. Chem. Soc. Faraday    Trans. 1995, 91, 4001-4003.-   (9) Kim, N.Y.; Laibinis, P. E. J. Am. Chem. Soc. 1997, 119,    2297-2298.-   (10) Zhu, X.-Y.; Boiadjiev, V.; Mulder, J. A.; Hsung, R. P.;    Major, R. C. Langmuir 2000, 16, 6766-6772.-   (11) Boukherroub, R.; Morin, S.; Sharpe, P.; Wayner, D. D. M.;    Allongue, P. Langmuir 2000, 16, 7429-7434.-   (12) Balakumar, A.; Lysenko, A. B.; Carcel, C.; Malinovskii, V. L.;    Gryko, D. T.; Schweikart, K.-H.; Loewe, R. S.; Yasseri, A. A.; Liu,    Z.; Bocian, D. F.; Lindsey, J. S. J. Org. Chem. 2004, 69, 1435-1443.-   (13) International Technology Roadmap for Semiconductors, 2003    Edition, http://public.itrs.net.-   (14) Linford, M. R.; Chidsey, C. E. D. J. Am. Chem. Soc. 1993, 115,    12631-12632.-   (15) Linford, M. R.; Fenter, P.; Eisenberger, P. M.;    Chidsey, C. E. D. J. Am. Chem. Soc. 1995, 117, 3145-3155.-   (16) Bansal, A.; Li, X.; Lauermann, I.; Lewis, N. S.; Yi, S. I.;    Weinberg, W. H. J. Am. Chem. Soc. 1996, 118, 7225-7226.-   (17) Allongue, P.; de Villeneuve, C. H.; Pinson, J.; Ozanam, F.;    Chazalviel, J. N.; Wallart, X. Electrochim. Acta 1998, 43,    2791-2798.-   (18) Gurtner, C.; Wun, A. W.; Sailor, M. J. Angew. Chem. Int. Ed.    1999, 38, 1966-1968.-   (19) Fellah, S.; Teyssot, A.; Ozanam, F.; Chazalviel, J.-N.;    Vigneron, J.; Etcheberry, A. Langmuir 2002, 18, 5851-5860.-   (20) Bateman, J. E.; Eagling, R. D.; Worrall, D. R.; Horrocks, B.    R.; Houlton, A. Angew. Chem. Int. Ed. 1998, 37, 2683-2685.-   (21) Boukherroub, R.; Morin, S.; Wayner, D. D. M.; Bensebaa, F.;    Sproule, G. I.; Baribeau, J.-M.; Lockwood, D. J. Chem. Mater. 2001,    13, 2002-2011.-   (22) Wagner, P.; Nock, S.; Spudich, J. A.; Volkmuth, W. D.; Chu, S.;    Cicero, R. L.; Wade, C. P.; Linford, M. R.; Chidsey, C. E. D. J.    Struct. Biol. 1997, 119, 189-201.-   (23) Boukherroub, R.; Wayner, D. D. M. J. Am. Chem. Soc. 1999, 121,    11513-11515.-   (24) Barrelet, C. J.; Robinson, D. B.; Cheng, J.; Hunt, T. P.;    Quate, C. F.; Chidsey, C. E. D. Langmuir 2001, 17, 3460-3465.-   (25) Zazzera, L. A.; Evans, J. F.; Deruelle, M.; Tirrell, M.;    Kessel, C. R.; Mckeown, P. J. Electrochem. Soc. 1997, 144,    2184-2189.-   (26) (a) Buriak, J. M.; Allen, M. J. J. Am. Chem. Soc. 1998, 120,    1339-1340. (b) Holland, J. M.; Stewart, M. P.; Allen, M. J.;    Buriak, J. M. J. Solid State Chem. 1999, 147, 251-258. (c)    Buriak, J. M.; Stewart, M. P.; Geders, T. W.; Allen, M. J.; Choi, H.    C.; Smith, J.; Raftery, D.; Canham, L. T. J. Am. Chem. Soc. 1999,    121, 11491-11502.-   (27) Cerofolini, G. F.; Galati, C.; Reina, S.; Renna, L. Semicond.    Sci. Technol. 2003, 18, 423-429.-   (28) Stewart, M. P.; Robins, E. G.; Geders, T. W.; Allen, M. J.;    Choi, H. C.; Buriak, J. M. Phys. Stat. Sol. 2000, 182, 109-115.-   (29) Wagner, R. W.; Ciringh, Y.; Clausen, C.; Lindsey, J. S. Chem.    Mater. 1999, 11, 2974-2983.-   (30) Loewe, R. S.; Ambroise, A.; Muthukumaran, K.; Padmaja, K.;    Lysenko, A. B.; Mathur, G.; Li, Q.; Bocian, D. F.; Misra, V.;    Lindsey, J. S. J. Org. Chem. 2004, 69, 1453-1460.-   (31) Wagner, R. W.; Johnson, T. E.; Lindsey, J. S. J. Am. Chem. Soc.    1996, 118, 11166-11180.-   (32) Wagner, R. W.; Johnson, T. E.; Li, F.; Lindsey, J. S. J. Org.    Chem. 1995, 60, 5266-5273.-   (33) Tamao, K.; Sumitani, K.; Kumada, M. J. Am. Chem. Soc. 1972, 94,    4374-4376.-   (34) Lindsey, J. S.; Prathapan, S.; Johnson, T. E.; Wagner, R. W.    Tetrahedron 1994, 50, 8941-8968.-   (35) Wagner, R. W.; Li, F.; Du, H.; Lindsey, J. S. Org. Process Res.    Dev. 1999, 3, 28-37.-   (36) Lindsey, J. S.; Wagner, R. W. J. Org. Chem. 1989, 54, 828-836.-   (37) Gryko, D. T.; Clausen, C.; Roth, K. M.; Dontha, N.; Bocian, D.    F.; Kuhr, W. G.; Lindsey, J. S. J. Org. Chem. 2000, 65, 7345-7355.-   (38) Lindsey, J. S.; Brown, P. A.; Siesel, D. A. Tetrahedron 1989,    45, 4845-4866.-   (39) Rao, P. D.; Dhanalekshmi, S.; Littler, B. J.; Lindsey, J. S. J.    Org. Chem. 2000, 65, 7323-7344.-   (40) Lee, C.-H.; Lindsey, J. S. Tetrahedron 1994, 50, 11427-11440.-   (41) Littler, B. J.; Miller, M. A.; Hung, C.-H.; Wagner, R. W.;    O'Shea, D. F.; Boyle, P. D.; Lindsey, J. S. J. Org. Chem. 1999, 64,    1391-1396.-   (42) Laha, J. K.; Dhanalekshmi, S.; Taniguchi, M.; Ambroise, A.;    Lindsey, J. S. Org. Process Res. Dev. 2003, 7, 799-812.-   (43) Wilson, G. S.; Anderson, H. L. Synlett 1996, 1039-1040.-   (44) Loewe, R. S.; Tomizaki, K.-Y.; Youngblood, W. J.; Bo, Z.;    Lindsey, J. S. J. Mater. Chem. 2002, 12, 3438-3451.-   (45) Tamaru, S.-I.; Yu, L.; Youngblood, W. J.; Muthukumaran, K.;    Taniguchi, M.; Lindsey, J. S. J. Org. Chem. 2004, 69, 765-777.-   (46) Geier, G. R., III; Callinan, J. B.; Rao, P. D.;    Lindsey, J. S. J. Porphyrins Phthalocyanines 2001, 5, 810-823.-   (47) (a) Fenyo, D.; Chait, B. T.; Johnson, T. E.; Lindsey, J. S. J.    Porphyrins Phthalocyanines 1997, 1, 93-99. (b) Srinivasan, N.;    Haney, C. A.; Lindsey, J. S.; Zhang, W.; Chait, B. T. J. Porphyrins    Phthalocyanines 1999, 3, 283-291.-   (48) Gryko, D.; Lindsey, J. S. J. Org. Chem. 2000, 65, 2249-2252.-   (49) Wang, Q. M.; Bruce, D. W. Synlett 1995, 1267-1268.-   (50) (a) Shultz, D. A.; Gwaltney, K. P.; Lee, H. J. Org. Chem. 1998,    63, 769-774. (b) Shanmugathasan, S.; Johnson, C. K.; Edwards, C.;    Matthews, E. K.; Dolphin, D.; Boyle, R. W. J. Porphyrins    Phthalocyanines 2000, 4, 228-232.-   (51) Stille, J. K. Angew. Chem. Int. Ed. Engl. 1986, 25, 508-524.-   (52) Clausen, C.; Gryko, D. T.; Yasseri, A. A.; Diers, J. R.;    Bocian, D. F.; Kuhr, W. G.; Lindsey, J. S. J. Org. Chem. 2000, 65,    7371-7378.-   (53) Lee, C.-H.; Li, F.; Iwamoto, K.; Dadok, J.; Bothner-By, A. A.;    Lindsey, J. S. Tetrahedron 1995, 51, 11645-11672.-   (54) Latos-Grazynski, L. In The Porphyrin Handbook; Kadish, K. M.,    Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego, Calif.,    2000; Vol. 2, pp 361-416.-   (55) Barbero, M.; Cadamuro, S.; Degani, I.; Dughera, S.; Fochi, R.;    Gatti, A.; Prandi, C. Gazz. Chim. Ital. 1990, 120, 619-627.-   (56) (a) Perlovich, G. L.; Golubchikov, O. A.; Klueva, M. E. J.    Porphyrins Phthalocyanines 2000, 4, 699-706. (b) Semyannikov, P. P.;    Basova, T. V.; Grankin, V. M.; Igumenov, I. K. J. Porphyrins    Phthalocyanines 2000, 4, 271-277. (c) Torres, L. A.; Campos, M.;    Enriquez, E.; Patiño, R. J. Chem. Thermodynamics 2002, 34, 293-302.

The foregoing is illustrative of the present invention, and is not to beconstrued as limiting thereof. The invention is defined by the followingclaims, with equivalents of the claims to be included therein.

1. A porphyrin compound having a surface attachment group coupledthereto at the 5 position, said surface attachment group having theformula:

wherein: R is —CHCH₂ or —CCH; Ar is an aromatic group; m is 2 to 4; n is1 to 6; and p is 1 to
 3. 2. The porphyrin compound of claim 1 wherein Ris —CCH.
 3. The porphyrin compound of claim 1 wherein R is —CHCH₂. 4.The porphyrin compound of claim 1 wherein Ar is a phenyl group.
 5. Amethod of making a porphyrin compound having a surface attachment groupcoupled thereto at the 5 position, said surface attachment group havingthe formula:

wherein: R is —CHCH₂ or —CCH; Ar is an aromatic group; m is 2 to 4; n is1 to 6; and p is 1 to 3, said method comprising: reacting adipyrromethane with a dipyrromethane-1,9-dicarbinol to produce areaction product; and then oxidizing said reaction product to producesaid porphyrin compound, wherein either or both of said dipyrromethaneand said dipyrromethane-1,9-dicarbinol is substituted with said surfaceattachment group at the 5 position.
 6. The method of claim 5, whereinsaid dipyrromethane-1,9-dicarbinol is produced by reducing a1,9-diacyldipyrromethane to form said dipyrromethane 1-9-dicarbinol.